\input texinfo    @c -*- texinfo -*-
@c %**start of header
@setfilename modus-themes.info
@settitle Modus themes for GNU Emacs
@documentencoding UTF-8
@documentlanguage en
@set MAINTAINERSITE @uref{https://protesilaos.com,maintainer webpage}
@set MAINTAINER Protesilaos Stavrou
@set MAINTAINEREMAIL @email{info@protesilaos.com}
@set MAINTAINERCONTACT @uref{mailto:info@protesilaos.com,contact the maintainer}
@c %**end of header

@copying
Copyright (C) 2020-2024 Free Software Foundation, Inc.

@quotation
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and
with the Back-Cover Texts as in (a) below.  A copy of the license is
included in the section entitled “GNU Free Documentation License.”

(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and
modify this GNU manual.”

@end quotation
@end copying

@dircategory Emacs misc features
@direntry
* Modus Themes: (modus-themes). Elegant, highly legible and customizable themes.
@end direntry

@finalout
@titlepage
@title Modus themes for GNU Emacs
@author Protesilaos Stavrou (@email{info@@protesilaos.com})
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@ifnottex
@node Top
@top Modus themes for GNU Emacs

@insertcopying

This manual, written by Protesilaos Stavrou, describes the customization
options for the @code{modus-operandi} and @code{modus-vivendi} themes, and provides
every other piece of information pertinent to them.

The documentation furnished herein corresponds to stable version
3.0.0, released on 2022-10-28.  Any reference to a newer
feature which does not yet form part of the latest tagged commit, is
explicitly marked as such.

Current development target is 3.1.0-dev.

@itemize
@item
Homepage: @uref{https://protesilaos.com/emacs/modus-themes}.
@item
Git repository: @uref{https://git.sr.ht/~protesilaos/modus-themes}.
@item
Mailing list: @uref{https://lists.sr.ht/~protesilaos/modus-themes}.
@item
Backronym: My Old Display Unexpectedly Sharpened @dots{} themes
@end itemize

@end ifnottex

@menu
* Overview::
* Installation::
* Enable and load::
* Customization Options::
* Advanced customization::
* Face coverage::
* Notes on individual packages::
* Frequently Asked Questions::
* Contributing::
* Acknowledgements::
* Other notes about the project::
* GNU Free Documentation License::
* Indices::

@detailmenu
--- The Detailed Node Listing ---

Overview

* How do the themes look like::
* Learn about the latest changes::

Installation

* Install manually from source::
* Install from the archives::
* Install on GNU/Linux::
* Dealing with byte compilation errors::

Install on GNU/Linux

* Debian 11 Bullseye::
* GNU Guix::

Enable and load

* Sample configuration with and without use-package::
* Differences between loading and enabling::

Customization Options

* Custom reload theme::          Toggle auto-reload of the theme when setting custom variables
* Deuteranopia style::           Toggle red/blue color-coding instead of red/green
* Bold constructs::              Toggle bold constructs in code
* Italic constructs::            Toggle italic font constructs in code
* Syntax styles::                Choose the overall aesthetic of code syntax
* Mixed fonts::                  Toggle mixing of font families
* Link styles::                  Choose among several styles, with or without underline
* Box buttons::                  Choose among several styles for buttons
* Command prompts::              Choose among plain, subtle, or intense prompts
* Mode line::                    Choose among several styles, with or without borders
* Tab style::                    Toggle accented background for tabs
* Completion UIs::               Choose among several styles for completion UIs
* Mail citations::               Choose among colorful, desaturated, monochrome citations
* Fringes::                      Choose among invisible, subtle, or intense fringe styles
* Language checkers::            Control the style of language checkers/linters
* Line highlighting::            Choose style of current line (hl-line-mode)
* Line numbers::                 Toggle subtle style for line numbers
* Mouse hover effects::          Toggle intense style for mouseover highlights
* Markup::                       Choose style for markup in Org and others
* Matching parentheses::         Choose between various styles for matching delimiters/parentheses
* Active region::                Choose between various styles for the active region
* Diffs::                        Choose among intense, desaturated, or background-only diffs
* Org mode blocks::              Choose among plain, gray, or tinted backgrounds
* Org agenda::                   Control each element in the presentation of the agenda
* Heading styles::               Choose among several styles, also per heading level
* UI typeface::                  Toggle the use of variable-pitch across the User Interface

Advanced customization

* More accurate colors in terminal emulators::
* Range of color with terminal emulators::
* Visualize the active Modus theme's palette::
* Per-theme customization settings::
* Case-by-case face specs using the themes' palette::
* Face specs at scale using the themes' palette::
* Remap face with local value::
* Cycle through arbitrary colors::
* Override colors::
* Override color saturation::
* Override colors through blending::
* Override colors completely::
* Font configurations for Org and others::
* Configure bold and italic faces::
* Custom Org todo keyword and priority faces::
* Custom Org emphasis faces::
* Update Org block delimiter fontification::
* Measure color contrast::
* Load theme depending on time of day::
* Backdrop for pdf-tools::
* Decrease mode line height::
* Toggle themes without reloading them::
* A theme-agnostic hook for theme loading::
* Diffs with only the foreground::
* Ediff without diff color-coding::
* Near-monochrome syntax highlighting::
* Custom hl-todo colors::
* Add support for solaire-mode::

Face coverage

* Supported packages::           Full list of covered face groups
* Indirectly covered packages::

Notes on individual packages

* Note on calendar.el weekday and weekend colors: Note on calendarel weekday and weekend colors. 
* Note on git-gutter in Doom Emacs::
* Note on php-mode multiline comments::
* Note on underlines in compilation buffers::
* Note on inline Latex in Org buffers::
* Note on dimmer.el: Note on dimmerel. 
* Note on display-fill-column-indicator-mode::
* Note on highlight-parentheses.el: Note on highlight-parenthesesel. 
* Note on mmm-mode.el background colors: Note on mmm-modeel background colors. 
* Note for prism::
* Note for god-mode::
* Note on company-mode overlay pop-up::
* Note on ERC escaped color sequences::
* Note on powerline or spaceline::
* Note on SHR colors::
* Note on SHR fonts::
* Note on Ement colors and fonts::
* Note on Helm grep::
* Note on pdf-tools link hints::
* Note on the Notmuch logo::
* Note on goto-address-mode faces::

Frequently Asked Questions

* Is the contrast ratio about adjacent colors?::
* What does it mean to avoid exaggerations?::
* Why are colors mostly variants of blue, magenta, cyan?: Why are colors mostly variants of blue magenta cyan?. 
* What is the best setup for legibility?::
* Are these color schemes?::
* Port the Modus themes to other platforms?::

Contributing

* Sources of the themes::
* Issues you can help with::
* Patches require copyright assignment to the FSF::

Indices

* Function index::
* Variable index::
* Concept index::

@end detailmenu
@end menu

@node Overview
@chapter Overview

The Modus themes are designed for accessible readability.  They conform
with the highest standard for color contrast between any given
combination of background and foreground values.  This corresponds to
the WCAG AAA standard, which specifies a minimum rate of distance in
relative luminance of 7:1.

Modus Operandi (@code{modus-operandi}) is a light theme, while Modus Vivendi
(@code{modus-vivendi}) is dark.  Each theme's color palette is designed to meet
the needs of the numerous interfaces that are possible in the Emacs
computing environment.

The overarching objective of this project is to always offer accessible
color combinations.  There shall never be a compromise on this
principle.  If there arises an inescapable trade-off between readability
and stylistic considerations, we will always opt for the former.

To ensure that users have a consistently accessible experience, the
themes strive to achieve as close to full face coverage as possible
(@ref{Face coverage}).

Furthermore, the themes are designed to empower users with red-green
color deficiency (deuteranopia).  This is achieved in three ways:

@enumerate
@item
The conformance with the highest legibility standard means that text
is always readable no matter the perception of its hue.

@item
Most contexts use colors on the blue-cyan-magenta-purple side of the
spectrum.  Put differently, green and/or red are seldom used, thus
minimizing the potential for confusion.

@ref{Why are colors mostly variants of blue magenta cyan?, , Why are colors mostly variants of blue@comma{} magenta@comma{} cyan?}.

@item
In contexts where a red/green color-coding is unavoidable, we provide
a universal toggle to customize the themes so that a red/blue scheme
is used instead.

@ref{Deuteranopia style, , Option for red-green color deficiency or deuteranopia}.
@end enumerate

Starting with version 0.12.0 and onwards, the themes are built into GNU
Emacs.

@menu
* How do the themes look like::
* Learn about the latest changes::
@end menu

@node How do the themes look like
@section How do the themes look like

@cindex Screenshots

Check the web page with @uref{https://protesilaos.com/emacs/modus-themes-pictures/, the screen shots}.  There are lots of scenarios
on display that draw attention to details and important aspects in the
design of the themes.  They also showcase the numerous customization
options.

@ref{Customization Options, , Customization options}.

@node Learn about the latest changes
@section Learn about the latest changes

@cindex Changelog

Please refer to the @uref{https://protesilaos.com/emacs/modus-themes-changelog, web page with the change log}.  It is comprehensive
and covers everything that goes into every tagged release of the themes.

@node Installation
@chapter Installation

The Modus themes are distributed with Emacs starting with version 28.1.
On older versions of Emacs, they can be installed using Emacs' package
manager or manually from their code repository.  There also exist
packages for distributions of GNU/Linux.

@menu
* Install manually from source::
* Install from the archives::
* Install on GNU/Linux::
* Dealing with byte compilation errors::
@end menu

@node Install manually from source
@section Install manually from source

In the following example, we are assuming that your Emacs files are
stored in @samp{~/.emacs.d} and that you want to place the Modus themes in
@samp{~/.emacs.d/modus-themes}.

@enumerate
@item
Get the source and store it in the desired path by running the
following in the command line shell:
@end enumerate

@example
$ git clone https://gitlab.com/protesilaos/modus-themes.git ~/.emacs.d/modus-themes
@end example


@enumerate
@item
Add that path to your known Elisp libraries' list, by placing this
snippet of Emacs Lisp in your init file (e.g. @file{init.el}):
@end enumerate

@lisp
(add-to-list 'load-path "~/.emacs.d/modus-themes")
@end lisp

The themes are now ready to be used: @ref{Enable and load}.

@node Install from the archives
@section Install from the archives

The @code{modus-themes} package is available from the GNU ELPA archive, which
is configured by default.

Prior to querying any package archive, make sure to update the index,
with @kbd{M-x package-refresh-contents}.  Then all you need to do
is type @kbd{M-x package-install} and specify the @code{modus-themes}.

Once installed, the themes are ready to be used: @ref{Enable and load}.

@node Install on GNU/Linux
@section Install on GNU/Linux

The themes are also available from the archives of some distributions of
GNU/Linux.  These should correspond to a tagged release rather than
building directly from the latest Git commit.  It all depends on the
distro's packaging policies.

@menu
* Debian 11 Bullseye::
* GNU Guix::
@end menu

@node Debian 11 Bullseye
@subsection Debian 11 Bullseye

The themes are part of Debian 11 Bullseye.  Get them with:

@example
sudo apt install elpa-modus-themes
@end example

They are now ready to be used: @ref{Enable and load}.

NOTE that Debian's package is severely out-of-date as of this writing
2022-07-24 09:57 +0300.

@node GNU Guix
@subsection GNU Guix

Users of Guix can get the themes with this command:

@example
guix package -i emacs-modus-themes
@end example

They are now ready to be used: @ref{Enable and load}.

@node Dealing with byte compilation errors
@section Dealing with byte compilation errors

From time to time, we receive bug reports pertaining to errors with byte
compilation.  These seldom have to do with faulty code in the themes: it
might be a shortcoming of @samp{package.el}, some regression in the current
development target of Emacs, a misconfiguration in an otherwise exotic
setup, and the like.

The common solution with a stable version of Emacs is to:

@enumerate
@item
Delete the @samp{modus-themes} package.
@item
Close the current Emacs session.
@item
Install the @samp{modus-themes} again.
@end enumerate

For those building Emacs directly from source, the solution may involve
reverting to an earlier commit in emacs.git.

At any rate, if you encounter such an issue please report it: we will
either fix the bug on our end if it is truly ours, or help forward it to
the relevant upstream maintainer.  Whatever you do, please understand
that a build failure does not mean we are necessarily doing something
wrong.

@ref{Issues you can help with}.

@node Enable and load
@chapter Enable and load

@findex modus-themes-load-themes
@findex modus-themes-toggle
@findex modus-themes-load-operandi
@findex modus-themes-load-vivendi
@cindex Essential configuration
@vindex modus-themes-after-load-theme-hook

Users of the built-in themes cannot @code{require} the package as usual
because there is no package to speak of.  Instead, things are simpler as
all one needs is to load the theme of their preference by adding either
form to their init file:

@lisp
(load-theme 'modus-operandi)            ; Light theme
(load-theme 'modus-vivendi)             ; Dark theme
@end lisp

Users of packaged variants of the themes must add a few more lines to
ensure that everything works as intended.  First, one has to require the
main library before loading either theme:

@lisp
(require 'modus-themes)
@end lisp

Then it is recommended to load the individual theme files with the
helper function @code{modus-themes-load-themes}:

@lisp
;; Load the theme files before enabling a theme (else you get an error).
(modus-themes-load-themes)
@end lisp

Once the libraries that define the themes are enabled, one can activate
a theme with either of the following expressions:

@lisp
(modus-themes-load-operandi)            ; Light theme
;; OR
(modus-themes-load-vivendi)             ; Dark theme
@end lisp

Changes to the available customization options must always be evaluated
before loading a theme (@ref{Customization Options}).  An exception to this
norm is when using the various Custom interfaces or with commands like
@kbd{M-x customize-set-variable}, which can optionally
automatically reload the theme (@ref{Custom reload theme, , Option for inhibiting theme reload}).

This is how a basic setup could look like:

@lisp
;;; For the built-in themes which cannot use `require':
;; Add all your customizations prior to loading the themes
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-region '(bg-only no-extend))

;; Load the theme of your choice:
(load-theme 'modus-operandi) ;; OR (load-theme 'modus-vivendi)

(define-key global-map (kbd "<f5>") #'modus-themes-toggle)



;;; For packaged versions which must use `require':
(require 'modus-themes)

;; Add all your customizations prior to loading the themes
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-region '(bg-only no-extend))

;; Load the theme files before enabling a theme
(modus-themes-load-themes)

;; Load the theme of your choice:
(modus-themes-load-operandi) ;; OR (modus-themes-load-vivendi)

(define-key global-map (kbd "<f5>") #'modus-themes-toggle)
@end lisp

@ref{Sample configuration with and without use-package}.

With those granted, bear in mind a couple of technical points on
@code{modus-themes-load-operandi} and @code{modus-themes-load-vivendi}, as well as
@code{modus-themes-toggle} which relies on them:

@enumerate
@item
Those functions call @code{load-theme}.  Some users prefer to opt for
@code{enable-theme} instead (@ref{Differences between loading and enabling}).

@item
The functions will run the @code{modus-themes-after-load-theme-hook} as
their final step.  This can be employed for bespoke configurations
(@ref{Advanced customization}).  Experienced users may not wish to rely on
such a hook and the functions that run it: they may prefer a custom
solution (@ref{A theme-agnostic hook for theme loading}).
@end enumerate

@menu
* Sample configuration with and without use-package::
* Differences between loading and enabling::
@end menu

@node Sample configuration with and without use-package
@section Sample configuration with and without use-package

@cindex use-package configuration
@cindex sample configuration

It is common for Emacs users to rely on @code{use-package} for declaring
package configurations in their setup.  We use this as an example:

@lisp
;;; For the built-in themes which cannot use `require':
(use-package emacs
  :init
  ;; Add all your customizations prior to loading the themes
  (setq modus-themes-italic-constructs t
        modus-themes-bold-constructs nil
        modus-themes-region '(bg-only no-extend))
  :config
  ;; Load the theme of your choice:
  (load-theme 'modus-operandi) ;; OR (load-theme 'modus-vivendi)
  :bind ("<f5>" . modus-themes-toggle))



;;; For packaged versions which must use `require':
(use-package modus-themes
  :ensure
  :init
  ;; Add all your customizations prior to loading the themes
  (setq modus-themes-italic-constructs t
        modus-themes-bold-constructs nil
        modus-themes-region '(bg-only no-extend))

  ;; Load the theme files before enabling a theme
  (modus-themes-load-themes)
  :config
  ;; Load the theme of your choice:
  (modus-themes-load-operandi) ;; OR (modus-themes-load-vivendi)
  :bind ("<f5>" . modus-themes-toggle))
@end lisp

The same without @code{use-package}:

@lisp
;;; For the built-in themes which cannot use `require':
;; Add all your customizations prior to loading the themes
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-region '(bg-only no-extend))

;; Load the theme of your choice:
(load-theme 'modus-operandi) ;; OR (load-theme 'modus-vivendi)

(define-key global-map (kbd "<f5>") #'modus-themes-toggle)



;;; For packaged versions which must use `require':
(require 'modus-themes)

;; Add all your customizations prior to loading the themes
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-region '(bg-only no-extend))

;; Load the theme files before enabling a theme
(modus-themes-load-themes)

;; Load the theme of your choice:
(modus-themes-load-operandi) ;; OR (modus-themes-load-vivendi)

(define-key global-map (kbd "<f5>") #'modus-themes-toggle)
@end lisp

@ref{Differences between loading and enabling}.

Note: make sure not to customize the variable @code{custom-theme-load-path}
or @code{custom-theme-directory} after the themes' package declaration.  That
will lead to failures in loading the files.  If either or both of those
variables need to be changed, their values should be defined before the
package declaration of the themes.

@node Differences between loading and enabling
@section Differences between loading and enabling

@cindex load-theme VS enable-theme

The reason we recommend @code{load-theme} instead of the other option of
@code{enable-theme} is that the former does a kind of ``reset'' on the face
specs.  It quite literally loads (or reloads) the theme.  Whereas the
latter simply puts an already loaded theme at the top of the list of
enabled items, re-using whatever state was last loaded.

As such, @code{load-theme} reads all customizations that may happen during
any given Emacs session: even after the initial setup of a theme.
Examples are calls to @code{custom-set-faces}, as well as new values assigned
to the options the Modus themes provide (@ref{Customization Options}).

Our tests show that @code{enable-theme} does not read such variables anew, so
it might appear to the unsuspecting user that the themes are somehow
broken whenever they try to assign a new value to a customization option
or some face.

This ``reset'' that @code{load-theme} brings about does, however, come at the
cost of being somewhat slower than @code{enable-theme}.  Users who have a
stable setup and who seldom update their variables during a given Emacs
session, are better off using something like this:

@lisp
(require 'modus-themes)
(load-theme 'modus-operandi t t)
(load-theme 'modus-vivendi t t)

(enable-theme 'modus-operandi) ;; OR (enable-theme 'modus-vivendi)
@end lisp

@ref{Toggle themes without reloading them}.

@ref{Sample configuration with and without use-package}.

With the above granted, other sections of the manual discuss how to
configure custom faces, where @code{load-theme} is expected, though
@code{enable-theme} could still apply in stable setups:

@ref{Case-by-case face specs using the themes' palette}.

@ref{Face specs at scale using the themes' palette}.

@node Customization Options
@chapter Customization Options

The Modus themes are highly configurable, though they should work well
without any further tweaks.  By default, all customization options are
set to nil, unless otherwise noted in this manual.

Remember that all customization options must be evaluated before loading
a theme (@ref{Enable and load}).  If the theme is already active, it must be
reloaded for changes in user options to come into force.

Below is a summary of what you will learn in the subsequent sections of
this manual.

@lisp
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-mixed-fonts nil
      modus-themes-subtle-line-numbers nil
      modus-themes-intense-mouseovers nil
      modus-themes-deuteranopia t
      modus-themes-tabs-accented t
      modus-themes-variable-pitch-ui nil
      modus-themes-inhibit-reload t ; only applies to `customize-set-variable' and related

      modus-themes-fringes nil ; @{nil,'subtle,'intense@}

      ;; Options for `modus-themes-lang-checkers' are either nil (the
      ;; default), or a list of properties that may include any of those
      ;; symbols: `straight-underline', `text-also', `background',
      ;; `intense' OR `faint'.
      modus-themes-lang-checkers nil

      ;; Options for `modus-themes-mode-line' are either nil, or a list
      ;; that can combine any of `3d' OR `moody', `borderless',
      ;; `accented', a natural number for extra padding (or a cons cell
      ;; of padding and NATNUM), and a floating point for the height of
      ;; the text relative to the base font size (or a cons cell of
      ;; height and FLOAT)
      modus-themes-mode-line '(accented borderless (padding . 4) (height . 0.9))

      ;; Same as above:
      ;; modus-themes-mode-line '(accented borderless 4 0.9)

      ;; Options for `modus-themes-markup' are either nil, or a list
      ;; that can combine any of `bold', `italic', `background',
      ;; `intense'.
      modus-themes-markup '(background italic)

      ;; Options for `modus-themes-syntax' are either nil (the default),
      ;; or a list of properties that may include any of those symbols:
      ;; `faint', `yellow-comments', `green-strings', `alt-syntax'
      modus-themes-syntax nil

      ;; Options for `modus-themes-hl-line' are either nil (the default),
      ;; or a list of properties that may include any of those symbols:
      ;; `accented', `underline', `intense'
      modus-themes-hl-line '(underline accented)

      ;; Options for `modus-themes-paren-match' are either nil (the
      ;; default), or a list of properties that may include any of those
      ;; symbols: `bold', `intense', `underline'
      modus-themes-paren-match '(bold intense)

      ;; Options for `modus-themes-links' are either nil (the default),
      ;; or a list of properties that may include any of those symbols:
      ;; `neutral-underline' OR `no-underline', `faint' OR `no-color',
      ;; `bold', `italic', `background'
      modus-themes-links '(neutral-underline background)

      ;; Options for `modus-themes-box-buttons' are either nil (the
      ;; default), or a list that can combine any of `flat', `accented',
      ;; `faint', `variable-pitch', `underline', `all-buttons', the
      ;; symbol of any font weight as listed in `modus-themes-weights',
      ;; and a floating point number (e.g. 0.9) for the height of the
      ;; button's text.
      modus-themes-box-buttons '(variable-pitch flat faint 0.9)

      ;; Options for `modus-themes-prompts' are either nil (the
      ;; default), or a list of properties that may include any of those
      ;; symbols: `background', `bold', `gray', `intense', `italic'
      modus-themes-prompts '(intense bold)

      ;; The `modus-themes-completions' is an alist that reads three
      ;; keys: `matches', `selection', `popup'.  Each accepts a nil
      ;; value (or empty list) or a list of properties that can include
      ;; any of the following (for WEIGHT read further below):
      ;;
      ;; `matches' - `background', `intense', `underline', `italic', WEIGHT
      ;; `selection' - `accented', `intense', `underline', `italic', `text-also' WEIGHT
      ;; `popup' - same as `selected'
      ;; `t' - applies to any key not explicitly referenced (check docs)
      ;;
      ;; WEIGHT is a symbol such as `semibold', `light', or anything
      ;; covered in `modus-themes-weights'.  Bold is used in the absence
      ;; of an explicit WEIGHT.
      modus-themes-completions '((matches . (extrabold))
                                 (selection . (semibold accented))
                                 (popup . (accented intense)))

      modus-themes-mail-citations nil ; @{nil,'intense,'faint,'monochrome@}

      ;; Options for `modus-themes-region' are either nil (the default),
      ;; or a list of properties that may include any of those symbols:
      ;; `no-extend', `bg-only', `accented'
      modus-themes-region '(bg-only no-extend)

      ;; Options for `modus-themes-diffs': nil, 'desaturated, 'bg-only
      modus-themes-diffs 'desaturated

      modus-themes-org-blocks 'gray-background ; @{nil,'gray-background,'tinted-background@}

      modus-themes-org-agenda ; this is an alist: read the manual or its doc string
      '((header-block . (variable-pitch 1.3))
        (header-date . (grayscale workaholic bold-today 1.1))
        (event . (accented varied))
        (scheduled . uniform)
        (habit . traffic-light))

      modus-themes-headings ; this is an alist: read the manual or its doc string
      '((1 . (overline background variable-pitch 1.3))
        (2 . (rainbow overline 1.1))
        (t . (semibold))))
@end lisp

@menu
* Custom reload theme::          Toggle auto-reload of the theme when setting custom variables
* Deuteranopia style::           Toggle red/blue color-coding instead of red/green
* Bold constructs::              Toggle bold constructs in code
* Italic constructs::            Toggle italic font constructs in code
* Syntax styles::                Choose the overall aesthetic of code syntax
* Mixed fonts::                  Toggle mixing of font families
* Link styles::                  Choose among several styles, with or without underline
* Box buttons::                  Choose among several styles for buttons
* Command prompts::              Choose among plain, subtle, or intense prompts
* Mode line::                    Choose among several styles, with or without borders
* Tab style::                    Toggle accented background for tabs
* Completion UIs::               Choose among several styles for completion UIs
* Mail citations::               Choose among colorful, desaturated, monochrome citations
* Fringes::                      Choose among invisible, subtle, or intense fringe styles
* Language checkers::            Control the style of language checkers/linters
* Line highlighting::            Choose style of current line (hl-line-mode)
* Line numbers::                 Toggle subtle style for line numbers
* Mouse hover effects::          Toggle intense style for mouseover highlights
* Markup::                       Choose style for markup in Org and others
* Matching parentheses::         Choose between various styles for matching delimiters/parentheses
* Active region::                Choose between various styles for the active region
* Diffs::                        Choose among intense, desaturated, or background-only diffs
* Org mode blocks::              Choose among plain, gray, or tinted backgrounds
* Org agenda::                   Control each element in the presentation of the agenda
* Heading styles::               Choose among several styles, also per heading level
* UI typeface::                  Toggle the use of variable-pitch across the User Interface
@end menu

@node Custom reload theme
@section Option for inhibiting theme reload

@vindex modus-themes-inhibit-reload

Brief: Toggle reloading of the active theme when an option is changed
through the Customize UI@.

Symbol: @code{modus-themes-inhibit-reload} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil}
@item
@code{t} (default)
@end enumerate

By default, customizing a theme-related user option through the Custom
interfaces or with @kbd{M-x customize-set-variable} will not reload the
currently active Modus theme.

Enable this behavior by setting this variable to @code{nil}.

Regardless of this option, the active theme must be reloaded for changes
to user options to take effect (@ref{Enable and load}).

@node Deuteranopia style
@section Option for red-green color deficiency or deuteranopia

@vindex modus-themes-deuteranopia

Brief: When non-@code{nil} use red/blue color-coding instead of red/green,
where appropriate.

Symbol: @code{modus-themes-deuteranopia} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

This is to account for red-green color deficiency, also know as
deuteranopia and variants.  It applies to all contexts where there can
be a color-coded distinction between failure or success, a to-do or done
state, a mark for deletion versus a mark for selection (e.g. in Dired),
current and lazily highlighted search matches, removed lines in diffs as
opposed to added ones, and so on.

Note that this does not change all colors throughout the active theme,
but only applies to cases that have color-coding significance.  For
example, regular code syntax highlighting is not affected.  There is no
such need because of the themes' overarching commitment to the highest
legibility standard, which ensures that text is readable regardless of
hue, as well as the predominance of colors on the
blue-cyan-magenta-purple side of the spectrum.

@ref{Why are colors mostly variants of blue magenta cyan?, , Why are colors mostly variants of blue@comma{} magenta@comma{} cyan?}.

@node Bold constructs
@section Option for more bold constructs

@vindex modus-themes-bold-constructs

Brief: Use bold for code syntax highlighting and related.

Symbol: @code{modus-themes-bold-constructs} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

The default is to use a bold typographic weight only when it is
required.

With a non-@code{nil} value (@code{t}) display several syntactic constructs in bold
weight.  This concerns keywords and other important aspects of code
syntax.  It also affects certain mode line indicators and command-line
prompts.

Advanced users may also want to configure the exact attributes of the
@code{bold} face.

@ref{Configure bold and italic faces}.

@node Italic constructs
@section Option for more italic constructs

@vindex modus-themes-italic-constructs

Brief: Use italics for code syntax highlighting and related.

Symbol: @code{modus-themes-italic-constructs} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

The default is to not use slanted text forms (italics) unless it is
absolutely necessary.

With a non-@code{nil} value (@code{t}) choose to render more faces in italics.  This
typically affects documentation strings and code comments.

Advanced users may also want to configure the exact attributes of the
@code{italic} face.

@ref{Configure bold and italic faces}.

@node Syntax styles
@section Option for syntax highlighting

@vindex modus-themes-syntax

Brief: Set the overall style of code syntax highlighting.

Symbol: @code{modus-themes-syntax} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{faint}
@item
@code{yellow-comments}
@item
@code{green-strings}
@item
@code{alt-syntax}
@end itemize

The default (a @code{nil} value or an empty list) is to use a balanced
combination of colors on the cyan-blue-magenta side of the spectrum.
There is little to no use of greens, yellows, and reds.  Comments are
gray, strings are blue colored, doc strings are a shade of cyan, while
color combinations are designed to avoid exaggerations.

The property @code{faint} fades the saturation of all applicable colors, where
that is possible or appropriate.

The property @code{yellow-comments} applies a yellow color to comments.

The property @code{green-strings} applies a green color to strings and a green
tint to doc strings.

The property @code{alt-syntax} changes the combination of colors beyond strings
and comments, so that the effective palette is broadened to provide
greater variety relative to the default.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(faint)
(green-strings yellow-comments)
(alt-syntax green-strings yellow-comments)
(faint alt-syntax green-strings yellow-comments)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-syntax '(faint alt-syntax))
@end lisp

Independent of this variable, users may also control the use of a bold
weight or italic text: @code{modus-themes-bold-constructs} and
@code{modus-themes-italic-constructs}.

@ref{Bold constructs, , Option for more bold constructs}.

@ref{Italic constructs, , Option for more italic constructs}.

@node Mixed fonts
@section Option for font mixing

@vindex modus-themes-mixed-fonts

Brief: Toggle the use of monospaced fonts for spacing-sensitive
constructs (affects font families).

Symbol: @code{modus-themes-mixed-fonts} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

When set to non-@code{nil} (@code{t}), configure some spacing-sensitive faces like Org
tables and code blocks to always inherit from the @code{fixed-pitch} face.
This is to ensure that certain constructs like code blocks and tables
remain monospaced even when users opt for a mode that remaps typeface
families, such as the built-in @kbd{M-x variable-pitch-mode}.  Otherwise
the layout would appear broken, due to how spacing is done.

For a consistent experience, user may need to specify the font family of
the @code{fixed-pitch} face.

@ref{Font configurations for Org and others}.

Furthermore, users may prefer to use another package for handling mixed
typeface configurations, rather than letting the theme do it, perhaps
because a purpose-specific package has extra functionality.  Two
possible options are @code{org-variable-pitch} and @code{mixed-pitch}.

@node Link styles
@section Option for links

@vindex modus-themes-links

Brief: Control the style of links to web pages, files, buffers@dots{}

Symbol: @code{modus-themes-links} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
Underline style:
@itemize
@item
@code{neutral-underline}
@item
@code{no-underline}
@end itemize
@item
Text coloration:
@itemize
@item
@code{faint}
@item
@code{no-color}
@end itemize
@item
@code{bold}
@item
@code{italic}
@item
@code{background}
@end itemize

The default (a @code{nil} value or an empty list) is a prominent text color,
typically blue, with an underline of the same color.

For the style of the underline, a @code{neutral-underline} property turns the
color of the line into a subtle gray, while the @code{no-underline} property
removes the line altogether.  If both of those are set, the latter takes
precedence.

For text coloration, a @code{faint} property desaturates the color of the text
and the underline, unless the underline is affected by the
aforementioned properties.  While a @code{no-color} property removes the color
from the text.  If both of those are set, the latter takes precedence.

A @code{bold} property applies a heavy typographic weight to the text of the
link.

An @code{italic} property adds a slant to the link's text (italic or oblique
forms, depending on the typeface).

A @code{background} property applies a subtle tinted background color.

In case both @code{no-underline} and @code{no-color} are set, then a subtle gray
background is applied to all links.  This can still be combined with the
@code{bold} and @code{italic} properties.

Combinations of any of those properties are expressed as a list,
like in these examples:

@lisp
(faint)
(no-underline faint)
(no-color no-underline bold)
(italic bold background no-color no-underline)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-links '(neutral-underline background))
@end lisp

The placement of the underline, meaning its proximity to the text, is
controlled by @code{x-use-underline-position-properties},
@code{x-underline-at-descent-line}, @code{underline-minimum-offset}.  Please refer to
their documentation strings.

@node Box buttons
@section Option for box buttons

@vindex modus-themes-box-buttons

Brief: Control the style of buttons in the Custom UI and related.

Symbol: @code{modus-themes-box-buttons} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{flat}
@item
@code{accented}
@item
@code{faint}
@item
@code{variable-pitch}
@item
@code{underline}
@item
A font weight, which must be supported by the underlying typeface:
@itemize
@item
@code{thin}
@item
@code{ultralight}
@item
@code{extralight}
@item
@code{light}
@item
@code{semilight}
@item
@code{regular}
@item
@code{medium}
@item
@code{semibold}
@item
@code{bold}
@item
@code{heavy}
@item
@code{extrabold}
@item
@code{ultrabold}
@end itemize
@item
A floating point as a height multiple of the default or a cons cell in
the form of @samp{(height . FLOAT)}
@item
@code{all-buttons}
@end itemize

The default (a @code{nil} value or an empty list) is a gray background
combined with a pseudo three-dimensional effect.

The @code{flat} property makes the button two dimensional.

The @code{accented} property changes the background from gray to an accent
color.

The @code{faint} property reduces the overall coloration.

The @code{variable-pitch} property applies a proportionately spaced typeface
to the button~s text.

@ref{Font configurations for Org and others}.

The @code{underline} property draws a line below the affected text and
removes whatever box effect.  This is optimal when Emacs runs inside a
terminal emulator (@ref{More accurate colors in terminal emulators}).  If
@code{flat} and @code{underline} are defined together, the latter takes
precedence.

The symbol of a weight attribute adjusts the font of the button
accordingly, such as @code{light}, @code{semibold}, etc.  Valid symbols are
defined in the variable @code{modus-themes-weights}.

@ref{Configure bold and italic faces}.

A number, expressed as a floating point (e.g. @samp{0.9}), adjusts the height
of the button's text to that many times the base font size.  The default
height is the same as @samp{1.0}, though it need not be explicitly stated.
Instead of a floating point, an acceptable value can be in the form of a
cons cell like @samp{(height . FLOAT)} or @samp{(height FLOAT)}, where FLOAT is
the given number.

The @code{all-buttons} property extends the box button effect (or the
aforementioned properties) to the faces of the generic widget library.
By default, those do not look like the buttons of the Custom UI as they
are ordinary text wrapped in square brackets.

Combinations of any of those properties are expressed as a list,
like in these examples:

@lisp
(flat)
(variable-pitch flat)
(variable-pitch flat semibold 0.9)
(variable-pitch flat semibold (height 0.9)) ; same as above
(variable-pitch flat semibold (height . 0.9)) ; same as above
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-box-buttons '(variable-pitch flat 0.9))
@end lisp

@node Command prompts
@section Option for command prompt styles

@vindex modus-themes-prompts

Brief: Control the style of command prompts (e.g. minibuffer, shell, IRC
clients).

Symbol: @code{modus-themes-prompts} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{background}
@item
@code{bold}
@item
@code{gray}
@item
@code{intense}
@item
@code{italic}
@end itemize

The default (a @code{nil} value or an empty list) means to only use a subtle
accented foreground color.

The property @code{background} applies a background color to the prompt's text.
By default, this is a subtle accented value.

The property @code{intense} makes the foreground color more prominent.  If the
@code{background} property is also set, it amplifies the value of the
background as well.

The property @code{gray} changes the prompt's colors to grayscale.  This
affects the foreground and, if the @code{background} property is also set, the
background.  Its effect is subtle, unless it is combined with the
@code{intense} property.

The property @code{bold} makes the text use a bold typographic weight.
Similarly, @code{italic} adds a slant to the font's forms (italic or oblique
forms, depending on the typeface).

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(intense)
(bold intense)
(intense bold gray)
(intense background gray bold)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-prompts '(background gray))
@end lisp

@node Mode line
@section Option for mode line presentation

@vindex modus-themes-mode-line

Brief: Control the style of the mode lines.

Symbol: @code{modus-themes-mode-line} (@samp{choice} type, list of properties)

Possible values, which can be expressed as a list of combinations of box
effect, color, and border visibility:

@itemize
@item
Overall style:
@itemize
@item
@code{3d}
@item
@code{moody}
@end itemize
@item
@code{accented}
@item
@code{borderless}
@item
A natural number > 1 for extra padding or a cons cell in the form of
@code{(padding . NATNUM)}.
@item
A floating point to set the height of the mode line's text.  It can
also be a cons cell in the form of @code{(height . FLOAT)}.
@end itemize

The default (a @code{nil} value or an empty list) is a two-dimensional
rectangle with a border around it.  The active and the inactive mode
lines use different shades of grayscale values for the background,
foreground, border.

The @code{3d} property applies a three-dimensional effect to the active mode
line.  The inactive mode lines remain two-dimensional and are toned down
a bit, relative to the default style.

The @code{moody} property optimizes the mode line for use with the library of
the same name (hereinafter referred to as 'Moody').  In practice, it
removes the box effect and replaces it with underline and overline
properties.  It also tones down the inactive mode lines.  Despite its
intended purpose, this option can also be used without the Moody library
(please consult the themes' manual on this point for more details).  If
both @code{3d} and @code{moody} properties are set, the latter takes precedence.

The @code{borderless} property removes the color of the borders.  It does not
actually remove the borders, but only makes their color the same as the
background, effectively creating some padding.

The @code{accented} property ensures that the active mode line uses a colored
background instead of the standard shade of gray.

A positive integer (natural number or natnum) applies a padding effect
of NATNUM pixels at the boundaries of the mode lines.  The default value
is 1 and does not need to be specified explicitly.  The padding has no
effect when the @code{moody} property is also used, because Moody already
applies its own tweaks.  To ensure that the underline is placed at the
bottom of the mode line, set @code{x-underline-at-descent-line} to non-@code{nil}
(this is not needed when the @code{borderless} property is also set).  For
users on Emacs 29, the @code{x-use-underline-position-properties} variable must
also be set to nil.

The padding can also be expressed as a cons cell in the form of
@samp{(padding . NATNUM)} or @samp{(padding NATNUM)} where the key is constant and
NATNUM is the desired natural number.

A floating point applies an adjusted height to the mode line's text as a
multiple of the main font size.  The default rate is 1.0 and does not
need to be specified.  Apart from a floating point, the height may also
be expressed as a cons cell in the form of @samp{(height . FLOAT)} or
@samp{(height FLOAT)} where the key is constant and the FLOAT is the desired
number.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(accented)
(borderless 3d)
(moody accented borderless)
@end lisp

Same as above, using the padding and height as an example (these
all yield the same result):

@lisp
(accented borderless 4 0.9)
(accented borderless (padding . 4) (height . 0.9))
(accented borderless (padding 4) (height 0.9))
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-mode-line '(borderless accented))
@end lisp

Note that Moody does not expose any faces that the themes could style
directly.  Instead it re-purposes existing ones to render its tabs and
ribbons.  As such, there may be cases where the contrast ratio falls
below the 7:1 target that the themes conform with (WCAG AAA).  To hedge
against this, we configure a fallback foreground for the @code{moody} property,
which will come into effect when the background of the mode line changes
to something less accessible, such as Moody ribbons (read the doc string
of @code{set-face-attribute}, specifically @code{:distant-foreground}).  This fallback
is activated when Emacs determines that the background and foreground of
the given construct are too close to each other in terms of color
distance.  In practice, users will need to experiment with the variable
@code{face-near-same-color-threshold} to trigger the effect.  We find that a
value of @samp{45000} shall suffice, contrary to the default @samp{30000}.  Though for
the combinations that involve the @code{accented} and @code{moody} properties, as
mentioned above, that should be raised up to @samp{70000}.  Do not set it too
high, because it has the adverse effect of always overriding the default
colors (which have been carefully designed to be highly accessible).

Furthermore, because Moody expects an underline and overline instead of
a box style, it is strongly advised to set @code{x-underline-at-descent-line}
to a non-@code{nil} value.

Finally, note that various packages which heavily modify the mode line,
such as @samp{doom-modeline}, @samp{nano-modeline}, @samp{powerline}, @samp{spaceline} may not look
as intended with all possible combinations of this user option.

@node Tab style
@section Option for accented background in tab interfaces

@vindex modus-themes-tabs-accented

Brief: Toggle accent colors for tabbed interfaces.

Symbol: @code{modus-themes-tabs-accented} (@samp{boolean} type)

Possible values:

@itemize
@item
@code{nil} (default)
@item
@code{t}
@end itemize

By default, all tab interfaces use backgrounds which are shades of gray.
When this option is set to non-@code{nil}, the backgrounds become colorful.

This affects the built-in @code{tab-bar-mode} and @code{tab-line-mode}, as well as the
Centaur tabs package.

@node Completion UIs
@section Option for completion framework aesthetics

@vindex modus-themes-completions

Brief: Set the overall style of completion framework interfaces.

Symbol: @code{modus-themes-completions} (@samp{alist} type properties)

This affects Company, Corfu, Flx, Helm, Icomplete/Fido, Ido, Ivy,
Orderless, Selectrum, Vertico.  The value is an alist that takes the
form of a @samp{(KEY . PROPERTIES)} combination.  @samp{KEY} is a symbol, while
@samp{PROPERTIES} is a list.  Here is a sample, followed by a description
of the particularities:

@lisp
(setq modus-themes-completions
      '((matches . (extrabold background intense))
        (selection . (semibold accented intense))
        (popup . (accented))))
@end lisp

The @code{matches} key refers to the highlighted characters that correspond
to the user's input.  When its properties are @code{nil} or an empty list,
matching characters in the user interface will have a bold weight and
a colored foreground.  The list of properties may include any of the
following symbols regardless of the order they may appear in:

@itemize
@item
@code{background} to add a background color;

@item
@code{intense} to increase the overall coloration (also amplifies
the @code{background}, if present);

@item
@code{underline} to draw a line below the characters;

@item
@code{italic} to use a slanted font (italic or oblique forms);

@item
The symbol of a font weight attribute such as @code{light}, @code{semibold}, et
cetera.  Valid symbols are defined in the @code{modus-themes-weights}
variable.  The absence of a weight means that bold will be used.
@end itemize

The @code{selection} key applies to the current line or currently matched
candidate, depending on the specifics of the user interface.  When its
properties are @code{nil} or an empty list, it has a subtle gray background,
a bold weight, and the base foreground value for the text.  The list
of properties it accepts is as follows (order is not significant):

@itemize
@item
@code{accented} to make the background colorful instead of gray;

@item
@code{text-also} to apply extra color to the text of the selected line;

@item
@code{intense} to increase the overall coloration;

@item
@code{underline} to draw a line below the characters;

@item
@code{italic} to use a slanted font (italic or oblique forms);

@item
The symbol of a font weight attribute such as @code{light}, @code{semibold}, et
cetera.  Valid symbols are defined in the @code{modus-themes-weights}
variable.  The absence of a weight means that bold will be used.
@end itemize

The @code{popup} key takes the same values as @code{selection}.  The only
difference is that it applies specifically to user interfaces that
display an inline popup and thus have slightly different styling
requirements than the minibuffer.  The two prominent packages are
@samp{company} and @samp{corfu}.

Apart from specifying each key separately, a fallback list is accepted.
This is only useful when the desired aesthetic is the same across all
keys that are not explicitly referenced.  For example, this:

@lisp
(setq modus-themes-completions
      '((t . (extrabold intense))))
@end lisp

Is the same as:

@lisp
(setq modus-themes-completions
      '((matches . (extrabold intense))
        (selection . (extrabold intense))
        (popup . (extrabold intense))))
@end lisp

In the case of the fallback, any property that does not apply to the
corresponding key is simply ignored (@code{matches} does not have @code{accented}
and @code{text-also}, while @code{selection} and @code{popup} do not have
@code{background}).

@ref{Configure bold and italic faces}.

Also refer to the documentation of the @code{orderless} package for its
intersection with @code{company} (if you choose to use those in tandem).

@node Mail citations
@section Option for mail citations

@vindex modus-themes-mail-citations

Brief: Set the overall style of citations/quotes when composing
emails.

Symbol: @code{modus-themes-mail-citations} (@samp{choice} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{intense}
@item
@code{faint}
@item
@code{monochrome}
@end enumerate

By default (a @code{nil} value) citations are styled with contrasting hues to
denote their depth.  Colors are easy to tell apart because they
complement each other, but they otherwise are not very prominent.

Option @code{intense} is similar to the default in terms of using contrasting
and complementary hues, but applies more saturated colors.

Option @code{faint} maintains the same color-based distinction between citation
levels though the colors it uses have subtle differences between them.

Option @code{monochrome} turns all quotes into a shade of gray.

Whatever the value assigned to this variable, citations in emails are
controlled by typographic elements or indentation, which the themes do
not touch.

@node Fringes
@section Option for fringe visibility

@vindex modus-themes-fringes

Brief: Control the overall coloration of the fringes.

Symbol: @code{modus-themes-fringes} (@samp{choice} type)

Possible values:

@enumerate
@item
@code{nil}
@item
@code{subtle}
@item
@code{intense}
@end enumerate

When the value is nil, do not apply a distinct background color.

With a value of @code{subtle} use a gray background color that is
visible yet close to the main background color.

With @code{intense} use a more pronounced gray background color.

@node Language checkers
@section Option for language checkers

@vindex modus-themes-lang-checkers

Brief: Control the style of in-buffer warnings and errors produced by
spell checkers, code linters, and the like.

Symbol: @code{modus-themes-lang-checkers} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{straight-underline}
@item
@code{text-also}
@item
@code{background}
@item
Overall coloration:
@itemize
@item
@code{intense}
@item
@code{faint}
@end itemize
@end itemize

The default (a @code{nil} value or an empty list) applies a color-coded
underline to the affected text, while it leaves the original foreground
intact.  If the display spec of Emacs has support for it, the
underline's style is that of a wave, otherwise it is a straight line.

The property @code{straight-underline} ensures that the underline under the
affected text is always drawn as a straight line.

The property @code{text-also} applies the same color of the underline to the
affected text.

The property @code{background} adds a color-coded background.

The property @code{intense} amplifies the applicable colors if @code{background}
and/or @code{text-also} are set.  If @code{intense} is set on its own, then it implies
@code{text-also}.

The property @code{faint} uses nuanced colors for the underline and for the
foreground when @code{text-also} is included.  If both @code{faint} and @code{intense} are
specified, the former takes precedence.

Combinations of any of those properties can be expressed in a list, as
in those examples:

@lisp
(background)
(straight-underline intense)
(background text-also straight-underline)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-lang-checkers '(text-also background))
@end lisp

NOTE: The placement of the straight underline, though not the wave
style, is controlled by the built-in variables @code{underline-minimum-offset},
@code{x-underline-at-descent-line}, @code{x-use-underline-position-properties}.

To disable fringe indicators for Flymake or Flycheck, refer to variables
@code{flymake-fringe-indicator-position} and @code{flycheck-indication-mode},
respectively.

@node Line highlighting
@section Option for line highlighting

@vindex modus-themes-hl-line

Brief: Control the style of the current line of @code{hl-line-mode}.

Symbol: @code{modus-themes-hl-line} (@samp{choice} type, list of properties)

The value is a list of properties, each designated by a symbol.  With
a @code{nil} value, or an empty list, the style is a subtle gray background
color.

Possible properties are the following symbols:

@itemize
@item
@code{accented}
@item
@code{intense}
@item
@code{underline}
@end itemize

The property @code{accented} changes the background to a colored variant.

An @code{underline} property draws a line below the highlighted area.  Its
color is similar to the background, so gray by default or an accent
color when @code{accented} is also set.

An @code{intense} property amplifies the colors in use, which may be both the
background and the underline.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(intense)
(underline intense)
(accented intense underline)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-hl-line '(underline accented))
@end lisp

Set @code{x-underline-at-descent-line} to a non-@code{nil} value so that the
placement of the underline coincides with the lower boundary of the
colored background.

This style affects several packages that enable @code{hl-line-mode}, such as
@samp{elfeed}, @samp{notmuch}, and @samp{mu4e}.

[ Also check the @samp{lin} package on GNU ELPA (by the author of the
  modus-themes) for a stylistic enhancement to @code{hl-line-mode}. ]

@node Line numbers
@section Option for line numbers

@vindex modus-themes-subtle-line-numbers

Brief: Toggle subtle line numbers.

Symbol: @code{modus-themes-subtle-line-numbers} (@samp{boolean} type)

Possible value:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

The default style for @code{display-line-numbers-mode} and its global variant
is to apply a subtle gray background to the line numbers.  The current
line has a more pronounced background and foreground combination to
bring more attention to itself.

Similarly, the faces for @code{display-line-numbers-major-tick} and its
counterpart @code{display-line-numbers-minor-tick} use appropriate styles that
involve a bespoke background and foreground combination.

With a non-@code{nil} value (@code{t}), line numbers have no background of their own.
Instead they retain the primary background of the theme, blending with
the rest of the buffer.  Foreground values for all relevant faces are
updated to accommodate this aesthetic.

@node Mouse hover effects
@section Option for mouseover effects

@vindex modus-themes-intense-mouseovers

Brief: Toggle intense mouse hover effects.

Symbol: @code{modus-themes-intense-mouseovers} (@samp{boolean} type)

Possible value:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

By default all mouseover effects apply a highlight with a subtle colored
background.  When non-@code{nil}, these have a more pronounced effect.

Note that this affects the generic @code{highlight} which, strictly speaking,
is not limited to mouse usage.

@node Markup
@section Option for markup style in Org and others

@vindex modus-themes-markup

Brief: Choose style of markup in Org, Markdown, and others (affects
constructs such as Org's @samp{=verbatim=} and @samp{~code~}).

Symbol: @code{modus-themes-markup} (@samp{boolean} type)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@enumerate
@item
@code{bold}
@item
@code{italic}
@item
@code{background}
@item
@code{intense}
@end enumerate

The @code{italic} property applies a typographic slant (italics).

The @code{bold} property applies a heavier typographic weight.

@ref{Configure bold and italic faces}.

The @code{background} property adds a background color.  The background is a
shade of gray, unless the @code{intense} property is also set.

The @code{intense} property amplifies the existing coloration.  When
@code{background} is used, the background color is enhanced as well and
becomes tinted instead of being gray.

Combinations of any of those properties are expressed as a list,
like in these examples:

@lisp
(bold)
(bold italic)
(bold italic intense)
(bold italic intense background)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-markup '(bold italic))
@end lisp

Also check the variables @code{org-hide-emphasis-markers},
@code{org-hide-macro-markers}.

@node Matching parentheses
@section Option for parenthesis matching

@vindex modus-themes-paren-match

Brief: Control the style of matching delimiters produced by
@code{show-paren-mode}.

Symbol: @code{modus-themes-paren-match} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{bold}
@item
@code{intense}
@item
@code{underline}
@end itemize

The default (a @code{nil} value or an empty list) is a subtle background color.

The @code{bold} property adds a bold weight to the characters of the matching
delimiters.

The @code{intense} property applies a more prominent background color to the
delimiters.

The @code{underline} property draws a straight line under the affected text.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(bold)
(underline intense)
(bold intense underline)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-paren-match '(bold intense))
@end lisp

This customization variable affects the built-in @code{show-paren-mode} and the
@samp{smartparens} package.

@node Active region
@section Option for active region

@vindex modus-themes-region

Brief: Control the style of the region.

Symbol: @code{modus-themes-region} (@samp{choice} type, list of properties)

Possible values are expressed as a list of properties (default is @code{nil} or
an empty list).  The list can include any of the following symbols:

@itemize
@item
@code{no-extend}
@item
@code{bg-only}
@item
@code{accented}
@end itemize

The default (a @code{nil} value or an empty list) is a prominent gray
background that overrides all foreground colors in the area it
encompasses.  Its reach extends to the edge of the window.

The @code{no-extend} property limits the region to the end of the line, so that
it does not reach the edge of the window.

The @code{bg-only} property makes the region's background color more subtle to
allow the underlying text to retain its foreground colors.

The @code{accented} property applies a more colorful background to the region.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(no-extend)
(bg-only accented)
(accented bg-only no-extend)
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-region '(bg-only no-extend))
@end lisp

@node Diffs
@section Option for diff buffer looks

@vindex modus-themes-diffs

Brief: Set the overall style of diffs.

Symbol: @code{modus-themes-diffs} (@samp{choice} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{desaturated}
@item
@code{bg-only}
@end enumerate

The default (@code{nil}) uses fairly intense color combinations for diffs, by
applying prominently colored backgrounds, with appropriately tinted
foregrounds.

Option @code{desaturated} follows the same principles as with the default
(@code{nil}), though it tones down all relevant colors.

Option @code{bg-only} applies a background but does not override the text's
foreground.  This makes it suitable for a non-@code{nil} value passed to
@code{diff-font-lock-syntax} (note: Magit does not support syntax highlighting
in diffs---last checked on 2021-12-02).

When the user option @code{modus-themes-deuteranopia} is non-@code{nil}, all diffs
will use a red/blue color-coding system instead of the standard
red/green.  Other stylistic changes are made in the interest of
optimizing for such a use-case.

@ref{Deuteranopia style, , Option for red-green color deficiency or deuteranopia}.

In versions before @samp{2.0.0} there was an option for foreground-only diffs.
This is no longer supported at the theme level because there are cases
where the perceived contrast and overall contextuality were not good
enough although the applied colors were technically above the 7:1
contrast threshold.

@ref{Diffs with only the foreground}.

@ref{Ediff without diff color-coding}.

@node Org mode blocks
@section Option for org-mode block styles

@vindex modus-themes-org-blocks

Brief: Set the overall style of Org code blocks, quotes, and the like.

Symbol: @code{modus-themes-org-blocks} (@samp{choice} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{gray-background} (value @code{grayscale} exists for backward compatibility)
@item
@code{tinted-background} (value @code{rainbow} exists for backward compatibility)
@end enumerate

Nil (the default) means that the block has no background of its own: it
uses the one that applies to the rest of the buffer.  In this case, the
delimiter lines have a gray color for their text, making them look
exactly like all other Org properties.

Option @code{gray-background} applies a subtle gray background to the block's
contents.  It also affects the begin and end lines of the block as they
get another shade of gray as their background, which differentiates them
from the contents of the block.  All background colors extend to the
edge of the window, giving the area a rectangular, ``blocky''
presentation.

Option @code{tinted-background} uses a slightly colored background for the
contents of the block.  The exact color will depend on the programming
language and is controlled by the variable @code{org-src-block-faces} (refer to
the theme's source code for the current association list).  For this to
take effect, the Org buffer needs to be restarted with @code{org-mode-restart}.
In this scenario, it may be better to inhibit the extension of the
delimiter lines' background to the edge of the window because Org does
not provide a mechanism to update their colors depending on the contents
of the block.  Disable the extension of such backgrounds by setting
@code{org-fontify-whole-block-delimiter-line} to nil.

Code blocks use their major mode's colors only when the variable
@code{org-src-fontify-natively} is non-@code{nil}.  While quote/verse blocks require
setting @code{org-fontify-quote-and-verse-blocks} to a non-@code{nil} value.

@ref{Update Org block delimiter fontification}.

Older versions of the themes provided options @code{grayscale} (or @code{greyscale})
and @code{rainbow}.  Those will continue to work as they are aliases for
@code{gray-background} and @code{tinted-background}, respectively.

@node Org agenda
@section Option for Org agenda constructs

@vindex modus-themes-org-agenda

Brief: Control the style of the Org agenda.  Multiple parameters are
available, each with its own options.

Symbol: @code{modus-themes-org-agenda} (@samp{alist} type, multiple styles)

This is an alist that accepts a @samp{(key . value)} combination.  Some values
are specified as a list.  Here is a sample, followed by a description of
all possible combinations:

@lisp
(setq modus-themes-org-agenda
      '((header-block . (variable-pitch 1.5))
        (header-date . (grayscale workaholic bold-today 1.2))
        (event . (accented italic varied))
        (scheduled . uniform)
        (habit . traffic-light)))
@end lisp

A @code{header-block} key applies to elements that concern the headings which
demarcate blocks in the structure of the agenda.  By default (a @code{nil}
value) those are rendered in a bold typographic weight, plus a height
that is slightly taller than the default font size.  Acceptable values
come in the form of a list that can include either or both of those
properties:

@itemize
@item
@code{variable-pitch} to use a proportionately spaced typeface;

@item
A number as a floating point (e.g. 1.5) to set the height of the text
to that many times the default font height.  A float of 1.0 or the
symbol @code{no-scale} have the same effect of making the font the same
height as the rest of the buffer.  When neither a number nor
`no-scale' are present, the default is a small increase in height (a
value of 1.15).

Instead of a floating point, an acceptable value can be in the form of
a cons cell like @samp{(height . FLOAT)} or @samp{(height FLOAT)}, where FLOAT
is the given number.

@item
The symbol of a weight attribute adjusts the font of the heading
accordingly, such as @code{light}, @code{semibold}, etc.  Valid symbols are
defined in the variable @code{modus-themes-weights}.  The absence of a
weight means that bold will be used by virtue of inheriting the @code{bold}
face.
@end itemize

@ref{Configure bold and italic faces}.

In case both a number and @code{no-scale} are in the list, the latter takes
precedence.  If two numbers are specified, the first one is applied.

Example usage:

@lisp
(header-block . nil)
(header-block . (1.5))
(header-block . (no-scale))
(header-block . (variable-pitch 1.5))
(header-block . (variable-pitch 1.5 semibold))
@end lisp

A @code{header-date} key covers date headings.  Dates use only a foreground
color by default (a @code{nil} value), with weekdays and weekends having a
slight difference in hueness.  The current date has an added gray
background.  This key accepts a list of values that can include any of
the following properties:

@itemize
@item
@code{grayscale} to make weekdays use the main foreground color and
weekends a more subtle gray;

@item
@code{workaholic} to make weekdays and weekends look the same in
terms of color;

@item
@code{bold-today} to apply a bold typographic weight to the current
date;

@item
@code{bold-all} to render all date headings in a bold weight;

@item
@code{underline-today} applies an underline to the current date while
removing the background it has by default;

@item
A number as a floating point (e.g. 1.2) to set the height of the text
to that many times the default font height.  The default is the same
as the base font height (the equivalent of 1.0).  Instead of a
floating point, an acceptable value can be in the form of a cons cell
like @samp{(height . FLOAT)} or @samp{(height FLOAT)}, where FLOAT is the given
number.
@end itemize

For example:

@lisp
(header-date . nil)
(header-date . (workaholic))
(header-date . (grayscale bold-all))
(header-date . (grayscale workaholic))
(header-date . (grayscale workaholic bold-today))
(header-date . (grayscale workaholic bold-today scale-heading))
@end lisp

An @code{event} key covers (i) headings with a plain time stamp that are
shown on the agenda, also known as events, (ii) entries imported from
the diary, and (iii) other items that derive from a symbolic expression
or sexp (phases of the moon, holidays, etc.).  By default all those look
the same and have a subtle foreground color (the default is a @code{nil} value
or an empty list).  This key accepts a list of properties.  Those are:

@itemize
@item
@code{accented} applies an accent value to the event's foreground,
replacing the original gray.  It makes all entries stand out more.
@item
@code{italic} adds a slant to the font's forms (italic or oblique forms,
depending on the typeface).
@item
@code{varied} differentiates between events with a plain time stamp and
entries that are generated from either the diary or a symbolic
expression.  It generally puts more emphasis on events.  When @code{varied}
is combined with @code{accented}, it makes only events use an accent color,
while diary/sexp entries retain their original subtle foreground.
When @code{varied} is used in tandem with @code{italic}, it applies a slant only
to diary and sexp entries, not events.  And when @code{varied} is the sole
property passed to the @code{event} key, it has the same meaning as the
list (italic varied).  The combination of @code{varied}, @code{accented},
@code{italic} covers all of the aforementioned cases.
@end itemize

For example:

@lisp
(event . nil)
(event . (italic))
(event . (accented italic))
(event . (accented italic varied))
@end lisp

A @code{scheduled} key applies to tasks with a scheduled date.  By default (a
@code{nil} value), those use varying shades of yellow to denote (i) a past or
current date and (ii) a future date.  Valid values are symbols:

@itemize
@item
@code{nil} (default);
@item
@code{uniform} to make all scheduled dates the same color;
@item
@code{rainbow} to use contrasting colors for past, present, future
scheduled dates.
@end itemize

For example:

@lisp
(scheduled . nil)
(scheduled . uniform)
(scheduled . rainbow)
@end lisp

A @code{habit} key applies to the @code{org-habit} graph.  All possible value are
passed as a symbol.  Those are:

@itemize
@item
The default (@code{nil}) is meant to conform with the original aesthetic of
@code{org-habit}.  It employs all four color codes that correspond to the
org-habit states---clear, ready, alert, and overdue---while
distinguishing between their present and future variants.  This
results in a total of eight colors in use: red, yellow, green, blue,
in tinted and shaded versions.  They cover the full set of information
provided by the @code{org-habit} consistency graph.
@item
@code{simplified} is like the default except that it removes the dichotomy
between current and future variants by applying uniform color-coded
values.  It applies a total of four colors: red, yellow, green, blue.
They produce a simplified consistency graph that is more legible (or
less busy) than the default.  The intent is to shift focus towards the
distinction between the four states of a habit task, rather than each
state's present/future outlook.
@item
@code{traffic-light} further reduces the available colors to red, yellow, and
green.  As in @code{simplified}, present and future variants appear
uniformly, but differently from it, the @code{clear} state is rendered in a
green hue, instead of the original blue.  This is meant to capture the
use-case where a habit task being too early is less important than it
being too late.  The difference between ready and clear states is
attenuated by painting both of them using shades of green.  This
option thus highlights the alert and overdue states.
@item
When @code{modus-themes-deuteranopia} is non-@code{nil} the exact style of the habit
graph adapts to the needs of users with red-green color deficiency by
substituting every instance of green with blue or cyan (depending on
the specifics).
@end itemize

@ref{Deuteranopia style, , Option for red-green color deficiency or deuteranopia}.

For example:

@lisp
(habit . nil)
(habit . simplified)
(habit . traffic-light)
@end lisp

Putting it all together, the alist can look like this:

@lisp
'((header-block . (1.5 variable-pitch))
  (header-date . (grayscale workaholic bold-today))
  (event . (accented varied))
  (scheduled . uniform)
  (habit . traffic-light))

;; Or else:
(setq modus-themes-org-agenda
      '((header-block . (1.5 variable-pitch))
        (header-date . (grayscale workaholic bold-today))
        (event . (accented varied))
        (scheduled . uniform)
        (habit . traffic-light)))
@end lisp

@node Heading styles
@section Option for the headings' overall style

@vindex modus-themes-headings

Brief: Heading styles with optional list of values for levels 0-8.

Symbol: @code{modus-themes-headings} (@samp{alist} type, multiple properties)

This is an alist that accepts a @samp{(key . list-of-values)} combination.
The key is either a number, representing the heading's level (0-8) or t,
which pertains to the fallback style.

Level 0 is a special heading: it is used for what counts as a document
title or equivalent, such as the @samp{#+title} construct we find in Org
files.  Levels 1-8 are regular headings.

The list of values covers symbols that refer to properties, as described
below.  Here is a complete sample, followed by a presentation of all
available properties:

@lisp
(setq modus-themes-headings
      '((1 . (background overline variable-pitch 1.5))
        (2 . (overline rainbow 1.3))
        (3 . (overline 1.1))
        (t . (monochrome))))
@end lisp

Properties:

@itemize
@item
@code{rainbow}
@item
@code{overline}
@item
@code{background}
@item
@code{monochrome}
@item
A font weight, which must be supported by the underlying typeface:
@itemize
@item
@code{thin}
@item
@code{ultralight}
@item
@code{extralight}
@item
@code{light}
@item
@code{semilight}
@item
@code{regular}
@item
@code{medium}
@item
@code{semibold}
@item
@code{bold}
@item
@code{heavy}
@item
@code{extrabold}
@item
@code{ultrabold}
@end itemize
@item
@code{no-bold} (deprecated alias of a @code{regular} weight)
@item
A floating point as a height multiple of the default or a cons cell in
the form of @samp{(height . FLOAT)}.
@end itemize

By default (a @code{nil} value for this variable), all headings have a bold
typographic weight and use a desaturated text color.

A @code{rainbow} property makes the text color more saturated.

An @code{overline} property draws a line above the area of the heading.

A @code{background} property adds a subtle tinted color to the background of
the heading.

A @code{monochrome} property makes the heading the same as the base color,
which is that of the @code{default} face's foreground.  When @code{background} is also
set, @code{monochrome} changes its color to gray.  If both @code{monochrome} and
@code{rainbow} are set, the former takes precedence.

A @code{variable-pitch} property changes the font family of the heading to that
of the @code{variable-pitch} face (normally a proportionately spaced typeface).

The symbol of a weight attribute adjusts the font of the heading
accordingly, such as @code{light}, @code{semibold}, etc.  Valid symbols are
defined in the variable @code{modus-themes-weights}.  The absence of a weight
means that bold will be used by virtue of inheriting the @code{bold} face.
For backward compatibility, the @code{no-bold} value is accepted, though
users are encouraged to specify a @code{regular} weight instead.

@ref{Configure bold and italic faces}.

A number, expressed as a floating point (e.g. 1.5), adjusts the height
of the heading to that many times the base font size.  The default
height is the same as 1.0, though it need not be explicitly stated.
Instead of a floating point, an acceptable value can be in the form of a
cons cell like @samp{(height . FLOAT)} or @samp{(height FLOAT)}, where FLOAT is
the given number.

Combinations of any of those properties are expressed as a list, like in
these examples:

@lisp
(semibold)
(rainbow background)
(overline monochrome semibold 1.3)
(overline monochrome semibold (height 1.3)) ; same as above
(overline monochrome semibold (height . 1.3)) ; same as above
@end lisp

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

@lisp
(setq modus-themes-headings
      '((1 . (background overline rainbow 1.5))
        (2 . (background overline 1.3))
        (t . (overline semibold))))
@end lisp

When defining the styles per heading level, it is possible to pass a
non-@code{nil} value (@code{t}) instead of a list of properties.  This will retain the
original aesthetic for that level.  For example:

@lisp
(setq modus-themes-headings
      '((1 . t)           ; keep the default style
        (2 . (background overline))
        (t . (rainbow)))) ; style for all other headings

(setq modus-themes-headings
      '((1 . (background overline))
        (2 . (rainbow semibold))
        (t . t))) ; default style for all other levels
@end lisp

For Org users, the extent of the heading depends on the variable
@code{org-fontify-whole-heading-line}.  This affects the @code{overline} and
@code{background} properties.  Depending on the version of Org, there may be
others, such as @code{org-fontify-done-headline}.

@node UI typeface
@section Option for variable-pitch font in UI elements

@vindex modus-themes-variable-pitch-ui

Brief: Toggle the use of proportionately spaced (@code{variable-pitch}) fonts
in the User Interface.

Symbol: @code{modus-themes-variable-pitch-ui} (@samp{boolean} type)

Possible values:

@enumerate
@item
@code{nil} (default)
@item
@code{t}
@end enumerate

This option concerns User Interface elements that are under the direct
control of Emacs.  In particular: the mode line, header line, tab bar,
and tab line.

The default is to use the same font as the rest of Emacs, which usually
is a monospaced family.

With a non-@code{nil} value (@code{t}) apply a proportionately spaced typeface.  This
is done by assigning the @code{variable-pitch} face to the relevant items.

@ref{Font configurations for Org and others}.

@node Advanced customization
@chapter Advanced customization

Unlike the predefined customization options which follow a clear pattern
of allowing the user to quickly specify their preference, the themes
also provide a more flexible, albeit difficult, mechanism to control
things with precision (@ref{Customization Options}).

This section is of interest only to users who are prepared to maintain
their own local tweaks and who are willing to deal with any possible
incompatibilities between versioned releases of the themes.  As such,
they are labeled as ``do-it-yourself'' or ``DIY''.

@menu
* More accurate colors in terminal emulators::
* Range of color with terminal emulators::
* Visualize the active Modus theme's palette::
* Per-theme customization settings::
* Case-by-case face specs using the themes' palette::
* Face specs at scale using the themes' palette::
* Remap face with local value::
* Cycle through arbitrary colors::
* Override colors::
* Override color saturation::
* Override colors through blending::
* Override colors completely::
* Font configurations for Org and others::
* Configure bold and italic faces::
* Custom Org todo keyword and priority faces::
* Custom Org emphasis faces::
* Update Org block delimiter fontification::
* Measure color contrast::
* Load theme depending on time of day::
* Backdrop for pdf-tools::
* Decrease mode line height::
* Toggle themes without reloading them::
* A theme-agnostic hook for theme loading::
* Diffs with only the foreground::
* Ediff without diff color-coding::
* Near-monochrome syntax highlighting::
* Custom hl-todo colors::
* Add support for solaire-mode::
@end menu

@node More accurate colors in terminal emulators
@section More accurate colors in terminal emulators

@cindex Color accuracy of terminal emulators

[ This is based on partial information.  Please help verify and/or
  expand these findings. ]

The graphical version of Emacs can reproduce color values accurately.
Whereas things get more tricky when Emacs is used in a terminal
emulator, because the terminals' own capabilities determine the number
of colors that may be displayed: the Modus themes don't look as good in
that case.

There is, however, a way to instruct supported terminal emulators to use
more accurate colors.  In a shell prompt type @samp{toe -a | grep direct} to
get a list of relevant terminfo entries.  There should be items such as
@samp{xterm-direct}, @samp{alacritty-direct}, @samp{kitty-direct}.  Once you find the one
that corresponds to your terminal, call Emacs with an environment
variable like @samp{TERM=xterm-direct}.  Example that can be adapted to shell
aliases:

@example
TERM=xterm-direct emacsclient -nw
@end example


Another example that can be bound to a key:

@example
TERM=xterm-direct uxterm -e emacsclient -nw
@end example

@node Range of color with terminal emulators
@section Range of color with terminal emulators

@cindex Pure white and pure black in terminal emulators

[ This is based on partial information.  Please help verify and/or
  expand these findings. ]

When Emacs runs in a non-windowed session its color reproduction
capacity is framed or determined by the underlying terminal emulator
(@ref{More accurate colors in terminal emulators}).  Emacs cannot produce a
color that lies outside the range of what the terminal's color palette
renders possible.

This is immediately noticeable when the terminal's first 16 codes do not
include a pure black value for the @samp{termcol0} entry and a pure white for
@samp{termcol15}.  Emacs cannot set the correct background (white for
@code{modus-operandi}; black for @code{modus-vivendi}) or foreground (inverse of
the background).  It thus falls back to the closest approximation, which
seldom is appropriate for the purposes of the Modus themes.

In such a case, the user is expected to update their terminal's color
palette such as by adapting these resources:

@lisp
! Theme: modus-operandi
! Description: XTerm port of modus-operandi (Modus themes for GNU Emacs)
! Author: Protesilaos Stavrou, <https://protesilaos.com>
xterm*background: #ffffff
xterm*foreground: #000000
xterm*color0:     #000000
xterm*color1:     #a60000
xterm*color2:     #005e00
xterm*color3:     #813e00
xterm*color4:     #0031a9
xterm*color5:     #721045
xterm*color6:     #00538b
xterm*color7:     #bfbfbf
xterm*color8:     #595959
xterm*color9:     #972500
xterm*color10:    #315b00
xterm*color11:    #70480f
xterm*color12:    #2544bb
xterm*color13:    #5317ac
xterm*color14:    #005a5f
xterm*color15:    #ffffff

! Theme: modus-vivendi
! Description: XTerm port of modus-vivendi (Modus themes for GNU Emacs)
! Author: Protesilaos Stavrou, <https://protesilaos.com>
xterm*background: #000000
xterm*foreground: #ffffff
xterm*color0:     #000000
xterm*color1:     #ff8059
xterm*color2:     #44bc44
xterm*color3:     #d0bc00
xterm*color4:     #2fafff
xterm*color5:     #feacd0
xterm*color6:     #00d3d0
xterm*color7:     #bfbfbf
xterm*color8:     #595959
xterm*color9:     #ef8b50
xterm*color10:    #70b900
xterm*color11:    #c0c530
xterm*color12:    #79a8ff
xterm*color13:    #b6a0ff
xterm*color14:    #6ae4b9
xterm*color15:    #ffffff
@end lisp

@node Visualize the active Modus theme's palette
@section Visualize the active Modus theme's palette

@findex modus-themes-list-colors
@findex modus-themes-list-colors-current
@cindex Preview color values

The command @code{modus-themes-list-colors} prompts for a choice between
@samp{modus-operandi} and @samp{modus-vivendi} to produce a help buffer that shows a
preview of each variable in the given theme's color palette.  The
command @code{modus-themes-list-colors-current} skips the prompt, using the
current Modus theme.

Each row shows a foreground and background coloration using the
underlying value it references.  For example a line with @samp{#a60000} (a
shade of red) will show red text followed by a stripe with that same
color as a backdrop.

The name of the buffer describes the given Modus theme.  It is thus
called @samp{*modus-operandi-list-colors*} or @samp{*modus-vivendi-list-colors*}.

@node Per-theme customization settings
@section Per-theme customization settings

If you prefer to maintain different customization options between the
two themes, it is best you write your own functions that first set those
options and then load the relevant theme.  The following code does
exactly that by simply differentiating the two themes on the choice of
bold constructs in code syntax (enabled for one, disabled for the
other).

@lisp
(defun my-demo-modus-operandi ()
  (interactive)
  (setq modus-themes-bold-constructs t) ; ENABLE bold
  (modus-themes-load-operandi))

(defun my-demo-modus-vivendi ()
  (interactive)
  (setq modus-themes-bold-constructs nil) ; DISABLE bold
  (modus-themes-load-vivendi))

(defun my-demo-modus-themes-toggle ()
  (if (eq (car custom-enabled-themes) 'modus-operandi)
      (my-demo-modus-vivendi)
    (my-demo-modus-operandi)))
@end lisp

Then assign @code{my-demo-modus-themes-toggle} to a key instead of the
equivalent the themes provide.

For a more elaborate design, it is better to inspect the source code of
@code{modus-themes-toggle} and relevant functions.

@node Case-by-case face specs using the themes' palette
@section Case-by-case face specs using the themes' palette

@findex modus-themes-color
@findex modus-themes-color-alts
@cindex Extracting individual colors

This section is about tweaking individual faces.  If you plan to do
things at scale, consult the next section: @ref{Face specs at scale using the themes' palette, , Set multiple faces}.

We already covered in previous sections how to toggle between the themes
and how to configure options prior to loading.  We also explained that
some of the functions made available to users will fire up a hook that
can be used to pass tweaks in the post-theme-load phase.

Now assume you wish to change a single face, say, the @code{cursor}.  And you
would like to get the standard ``blue'' color value of the active Modus
theme, whether it is Modus Operandi or Modus Vivendi.  To do that, you
can use the @code{modus-themes-color} function.  It accepts a symbol that is
associated with a color in @code{modus-themes-operandi-colors} and
@code{modus-themes-vivendi-colors}.  Like this:

@lisp
(modus-themes-color 'blue)
@end lisp

The function always extracts the color value of the active Modus theme.

@lisp
(progn
  (load-theme 'modus-operandi t)
  (modus-themes-color 'blue))           ; "#0031a9" for `modus-operandi'

(progn
  (load-theme 'modus-vivendi t)
  (modus-themes-color 'blue))           ; "#2fafff" for `modus-vivendi'
@end lisp

Do @kbd{C-h v} on the aforementioned variables to check all the available
symbols that can be passed to this function.  Or simply invoke the
command @code{modus-themes-list-colors} to produce a buffer with a preview of
each entry in the palette.

@ref{Visualize the active Modus theme's palette}.

With that granted, let us expand the example to actually change the
@code{cursor} face's background property.  We employ the built-in function of
@code{set-face-attribute}:

@lisp
(set-face-attribute 'cursor nil :background (modus-themes-color 'blue))
@end lisp

If you evaluate this form, your cursor will become blue.  But if you
change themes, such as with @code{modus-themes-toggle}, your edits will be
lost, because the newly loaded theme will override the @code{:background}
attribute you had assigned to that face.

For such changes to persist, we need to make them after loading the
theme.  So we rely on @code{modus-themes-after-load-theme-hook}, which gets
called from @code{modus-themes-load-operandi}, @code{modus-themes-load-vivendi}, as
well as the command @code{modus-themes-toggle}.  Here is a sample function that
tweaks two faces and then gets added to the hook:

@lisp
(defun my-modus-themes-custom-faces ()
  (set-face-attribute 'cursor nil :background (modus-themes-color 'blue))
  (set-face-attribute 'font-lock-type-face nil :foreground (modus-themes-color 'magenta-alt)))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

@ref{A theme-agnostic hook for theme loading}.

Using this principle, it is possible to override the styles of faces
without having to find color values for each case.

Another application is to control the precise weight for bold
constructs.  This is particularly useful if your typeface has several
variants such as ``heavy'', ``extrabold'', ``semibold''.  All you have to do
is edit the @code{bold} face.  For example:

@lisp
(set-face-attribute 'bold nil :weight 'semibold)
@end lisp

Remember to use the custom function and hook combo we demonstrated
above.  Because the themes do not hard-wire a specific weight, this
simple form is enough to change the weight of all bold constructs
throughout the interface.

Finally, there are cases where you want to tweak colors though wish to
apply different ones to each theme, say, a blue hue for Modus Operandi
and a shade of red for Modus Vivendi.  To this end, we provide
@code{modus-themes-color-alts} as a convenience function to save you from the
trouble of writing separate wrappers for each theme.  It still returns a
single value by querying either of @code{modus-themes-operandi-colors} and
@code{modus-themes-vivendi-colors}, only here you pass the two keys you want,
first for @code{modus-operandi} then @code{modus-vivendi}.

Take the previous example with the @code{cursor} face:

@lisp
;; Blue for `modus-operandi' and red for `modus-vivendi'
(set-face-attribute 'cursor nil :background (modus-themes-color-alts 'blue 'red))
@end lisp

@node Face specs at scale using the themes' palette
@section Face specs at scale using the themes' palette

@findex modus-themes-with-colors
@cindex Extracting colors en masse

The examples here are for large scale operations.  For simple, one-off
tweaks, you may prefer the approach documented in the previous section
(@ref{Case-by-case face specs using the themes' palette}).

The @code{modus-themes-with-colors} macro lets you retrieve multiple color
values by employing the backquote/backtick and comma notation.  The
values are stored in the alists @code{modus-themes-operandi-colors} and
@code{modus-themes-vivendi-colors}, while the macro always queries that of the
active Modus theme (preview the current palette with the command
@code{modus-themes-list-colors}).

@ref{Visualize the active Modus theme's palette}.

Here is an abstract example that just returns a list of color values
while @code{modus-operandi} is enabled:

@lisp
(modus-themes-with-colors
  (list fg-main
        blue-faint
        magenta
        magenta-alt-other
        cyan-alt-other
        fg-special-cold
        blue-alt
        magenta-faint
        cyan
        fg-main
        green-faint
        red-alt-faint
        blue-alt-faint
        fg-special-warm
        cyan-alt
        blue))
;; =>
;; ("#000000" "#002f88" "#721045" "#5317ac"
;;  "#005a5f" "#093060" "#2544bb" "#752f50"
;;  "#00538b" "#000000" "#104410" "#702f00"
;;  "#003f78" "#5d3026" "#30517f" "#0031a9")
@end lisp

Getting a list of colors may have its applications, though what you are
most likely interested in is how to use those variables to configure
several faces at once.  To do so we can rely on the built-in
@code{custom-set-faces} function, which sets face specifications for the
special @code{user} theme.  That ``theme'' gets applied on top of regular themes
like @code{modus-operandi} and @code{modus-vivendi}.

This is how it works:

@lisp
(modus-themes-with-colors
  (custom-set-faces
   `(cursor ((,class :background ,blue)))
   `(mode-line ((,class :background ,yellow-nuanced-bg
                        :foreground ,yellow-nuanced-fg)))
   `(mode-line-inactive ((,class :background ,blue-nuanced-bg
                                 :foreground ,blue-nuanced-fg)))))
@end lisp

The above snippet will immediately refashion the faces it names once it
is evaluated.  However, if you switch between the Modus themes, say,
from @code{modus-operandi} to @code{modus-vivendi}, the colors will not get updated to
match those of the new theme.  To make things work across the themes, we
need to employ the same technique we discussed in the previous section,
namely, to pass our changes at the post-theme-load phase via a hook.

The themes provide the @code{modus-themes-after-load-theme-hook}, which gets
called from @code{modus-themes-load-operandi}, @code{modus-themes-load-vivendi}, as
well as the command @code{modus-themes-toggle}.  With this knowledge, you can
wrap the macro in a function and then assign that function to the hook.
Thus:

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(cursor ((,class :background ,blue)))
     `(mode-line ((,class :background ,yellow-nuanced-bg
                          :foreground ,yellow-nuanced-fg)))
     `(mode-line-inactive ((,class :background ,blue-nuanced-bg
                                   :foreground ,blue-nuanced-fg))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

@ref{A theme-agnostic hook for theme loading}.

To discover the faces defined by all loaded libraries, you may do
@kbd{M-x list-faces-display}.  Be warned that when you @code{:inherit} a face
you are introducing an implicit dependency, so try to avoid doing so for
libraries other than the built-in @file{faces.el} (or at least understand
that things may break if you inherit from a yet-to-be-loaded face).

Also bear in mind that these examples are meant to work with the Modus
themes.  If you are cycling between multiple themes you may encounter
unforeseen issues, such as the colors of the Modus themes being applied
to a non-Modus item.

Finally, note that you can still use other functions where those make
sense.  For example, the @code{modus-themes-color-alts} that was discussed in
the previous section.  Adapt the above example like this:

@lisp
...
(modus-themes-with-colors
  (custom-set-faces
   `(cursor ((,class :background ,(modus-themes-color-alts 'blue 'green))))
   ...))
@end lisp

@node Remap face with local value
@section Remap face with local value

@cindex Remapping faces

There are cases where we need to change the buffer-local attributes of a
face.  This might be because we have our own minor mode that re-uses a
face for a particular purpose, such as a line selection tool that
activates @code{hl-line-mode}, but we wish to keep it distinct from other
buffers.  This is where @code{face-remap-add-relative} can be applied and may
be combined with @code{modus-themes-with-colors} to deliver consistent results.

@ref{Face specs at scale using the themes' palette}.

In this example we will write a simple interactive function that adjusts
the background color of the @code{region} face.  This is the sample code:

@lisp
(defvar my-rainbow-region-colors
  (modus-themes-with-colors
    `((red . ,red-subtle-bg)
      (green . ,green-subtle-bg)
      (yellow . ,yellow-subtle-bg)
      (blue . ,blue-subtle-bg)
      (magenta . ,magenta-subtle-bg)
      (cyan . ,cyan-subtle-bg)))
  "Sample list of color values for `my-rainbow-region'.")

(defun my-rainbow-region (color)
  "Remap buffer-local attribute of `region' using COLOR."
  (interactive
   (list
    (completing-read "Pick a color: " my-rainbow-region-colors)))
  (face-remap-add-relative
   'region
   `( :background ,(alist-get (intern color) my-rainbow-region-colors)
      :foreground ,(face-attribute 'default :foreground))))
@end lisp

When @code{my-rainbow-region} is called interactively, it prompts for a color
to use.  The list of candidates is drawn from the car of each
association in @code{my-rainbow-region-colors} (so ``red'', ``green'', etc.).

To extend this principle, we may write wrapper functions that pass a
color directly.  Those can be useful in tandem with hooks.  Consider
this example:

@lisp
(defun my-rainbow-region-magenta ()
  (my-rainbow-region 'magenta))

(add-hook 'diff-mode-hook #'my-rainbow-region-magenta)
@end lisp

Whenever we enter a @code{diff-mode} buffer, we now get a magenta-colored
region.

Perhaps you may wish to generalize those findings in to a set of
functions that also accept an arbitrary face.  We shall leave the
experimentation up to you.

@node Cycle through arbitrary colors
@section Cycle through arbitrary colors

@cindex Cycle colors

Users may opt to customize individual faces of the themes to accommodate
their particular needs.  One such case is with the color intensity of
comments, specifically the foreground of @code{font-lock-comment-face}.  The
Modus themes set that to a readable value, in accordance with their
accessibility objective, though users may prefer to lower the overall
contrast on an on-demand basis.

One way to achieve this is to design a command that cycles through three
distinct levels of intensity, though the following can be adapted to any
kind of cyclic behavior, such as to switch between red, green, and blue.

In the following example, we employ the @code{modus-themes-color} function
which reads a symbol that represents an entry in the active theme's
color palette (@ref{Case-by-case face specs using the themes' palette}).
Those are stored in @code{my-modus-themes-comment-colors}.

@lisp
(defvar my-modus-themes-comment-colors
  ;; We are abusing the palette here, as those colors have their own
  ;; purpose in the palette, so please ignore the semantics of their
  ;; names.
  '((low . bg-region)
    (medium . bg-tab-inactive-alt)
    (high . fg-alt))
  "Alist of levels of intensity mapped to color palette entries.
The entries are found in `modus-themes-operandi-colors' or
`modus-themes-vivendi-colors'.")

(defvar my-modus-themes--adjust-comment-color-state nil
  "The cyclic state of `my-modus-themes-adjust-comment-color'.
For internal use.")

(defun my-modus-themes--comment-foreground (degree state)
  "Set `font-lock-comment-face' foreground.
Use `my-modus-themes-comment-colors' to extract the color value
for each level of intensity.

This is complementary to `my-modus-themes-adjust-comment-color'."
  (let ((palette-colors my-modus-themes-comment-colors))
    (set-face-foreground
     'font-lock-comment-face
     (modus-themes-color (alist-get degree palette-colors)))
    (setq my-modus-themes--adjust-comment-color-state state)
    (message "Comments are set to %s contrast" degree)))

(defun my-modus-themes-adjust-comment-color ()
  "Cycle through levels of intensity for comments.
The levels are determined by `my-modus-themes-comment-colors'."
  (interactive)
  (pcase my-modus-themes--adjust-comment-color-state
    ('nil
     (my-modus-themes--comment-foreground 'low 1))
    (1
     (my-modus-themes--comment-foreground 'medium 2))
    (_
     (my-modus-themes--comment-foreground 'high nil))))
@end lisp

With the above, @kbd{M-x my-modus-themes-adjust-comment-color} will cycle
through the three levels of intensity that have been specified.

Another approach is to not read from the active theme's color palette
and instead provide explicit color values, either in hexadecimal RGB
notation (like @samp{#123456}) or as the names that are displayed in the output
of @kbd{M-x list-colors-display}.  In this case, the alist with the
colors will have to account for the active theme, so as to set the
appropriate colors.  While this introduces a bit more complexity, it
ultimately offers greater flexibility on the choice of colors for such a
niche functionality (so there is no need to abuse the palette of the
active Modus theme):

@lisp
(defvar my-modus-themes-comment-colors
  '((light . ((low . "gray75")
              (medium . "gray50")
              (high . "#505050")))      ; the default for `modus-operandi'

    (dark . ((low . "gray25")
             (medium . "gray50")
             (high . "#a8a8a8"))))      ; the default for `modus-vivendi'
  "Alist of levels of intensity mapped to color values.
For such colors, consult the command `list-colors-display'.  Pass
the name of a color or its hex value.")

(defvar my-modus-themes--adjust-comment-color-state nil
  "The cyclic state of `my-modus-themes-adjust-comment-color'.
For internal use.")

(defun my-modus-themes--comment-foreground (degree state)
    "Set `font-lock-comment-face' foreground.
Use `my-modus-themes-comment-colors' to extract the color value
for each level of intensity.

This is complementary to `my-modus-themes-adjust-comment-color'."
  (let* ((colors my-modus-themes-comment-colors)
         (levels (pcase (car custom-enabled-themes)
                   ('modus-operandi (alist-get 'light colors))
                   ('modus-vivendi (alist-get 'dark colors)))))
    (set-face-foreground
     'font-lock-comment-face
     (alist-get degree levels))
    (setq my-modus-themes--adjust-comment-color-state state)
    (message "Comments are set to %s contrast" degree)))

(defun my-modus-themes-adjust-comment-color ()
  "Cycle through levels of intensity for comments.
The levels are determined by `my-modus-themes-comment-colors'."
  (interactive)
  (pcase my-modus-themes--adjust-comment-color-state
    ('nil
     (my-modus-themes--comment-foreground 'low 1))
    (1
     (my-modus-themes--comment-foreground 'medium 2))
    (_
     (my-modus-themes--comment-foreground 'high nil))))
@end lisp

The effect of the above configurations on @code{font-lock-comment-face} is
global.  To make it buffer-local, one must tweak the code to employ the
function @code{face-remap-add-relative} (@ref{Remap face with local value}).

So this form in @code{my-modus-themes--comment-foreground}:

@lisp
;; example 1
(...
 (set-face-foreground
  'font-lock-comment-face
  (modus-themes-color (alist-get degree palette-colors)))
 ...)

;; example 2
(...
 (set-face-foreground
  'font-lock-comment-face
  (alist-get degree levels))
 ...)
@end lisp

Must become this:

@lisp
;; example 1
(...
 (face-remap-add-relative
  'font-lock-comment-face
  `(:foreground ,(modus-themes-color (alist-get degree palette-colors))))
 ...)

;; example 2
(...
 (face-remap-add-relative
  'font-lock-comment-face
  `(:foreground ,(alist-get degree levels)))
 ...)
@end lisp

@node Override colors
@section Override colors

@vindex modus-themes-operandi-color-overrides
@vindex modus-themes-vivendi-color-overrides
@cindex Change a theme's colors

The themes provide a mechanism for overriding their color values.  This
is controlled by the variables @code{modus-themes-operandi-color-overrides} and
@code{modus-themes-vivendi-color-overrides}, which are alists that should
mirror a subset of the associations in @code{modus-themes-operandi-colors} and
@code{modus-themes-vivendi-colors} respectively.  As with all customizations,
overriding must be done before loading the affected theme.

@ref{Visualize the active Modus theme's palette}.

Let us approach the present topic one step at a time.  Here is a
simplified excerpt of the default palette for Modus Operandi with some
basic background values that apply to buffers and the mode line
(remember to inspect the actual value to find out all the associations
that can be overridden):

@lisp
(defconst modus-themes-operandi-colors
  '((bg-main . "#ffffff")
    (bg-dim . "#f8f8f8")
    (bg-alt . "#f0f0f0")
    (bg-active . "#d7d7d7")
    (bg-inactive . "#efefef")))
@end lisp

As one can tell, we bind a key to a hexadecimal RGB color value.  Now
say we wish to override those specific values and have our changes
propagate to all faces that use those keys.  We could write something
like this, which adds a subtle ocher tint:

@lisp
(setq modus-themes-operandi-color-overrides
      '((bg-main . "#fefcf4")
        (bg-dim . "#faf6ef")
        (bg-alt . "#f7efe5")
        (bg-active . "#e8dfd1")
        (bg-inactive . "#f6ece5")))
@end lisp

Once this is evaluated, any subsequent loading of @code{modus-operandi} will
use those values instead of the defaults.  No further intervention is
required.

To reset the changes, we apply this and reload the theme:

@lisp
(setq modus-themes-operandi-color-overrides nil)
@end lisp

Users who wish to leverage such a mechanism can opt to implement it
on-demand by means of a global minor mode.  The following snippet covers
both themes and expands to some more associations in the palette:

@lisp
(define-minor-mode my-modus-themes-tinted
  "Tweak some Modus themes colors."
  :init-value nil
  :global t
  (if my-modus-themes-tinted
      (setq modus-themes-operandi-color-overrides
            '((bg-main . "#fefcf4")
              (bg-dim . "#faf6ef")
              (bg-alt . "#f7efe5")
              (bg-hl-line . "#f4f0e3")
              (bg-active . "#e8dfd1")
              (bg-inactive . "#f6ece5")
              (bg-region . "#c6bab1")
              (bg-header . "#ede3e0")
              (bg-tab-active . "#fdf6eb")
              (bg-tab-inactive . "#c8bab8"))
            modus-themes-vivendi-color-overrides
            '((bg-main . "#100b17")
              (bg-dim . "#161129")
              (bg-alt . "#181732")
              (bg-hl-line . "#191628")
              (bg-active . "#282e46")
              (bg-inactive . "#1a1e39")
              (bg-region . "#393a53")
              (bg-header . "#202037")
              (bg-tab-active . "#120f18")
              (bg-tab-inactive . "#3a3a5a")))
    (setq modus-themes-operandi-color-overrides nil
          modus-themes-vivendi-color-overrides nil)))
@end lisp

A more neutral style for @code{modus-themes-operandi-color-overrides} can
look like this:

@lisp
'((bg-main . "#f7f7f7")
  (bg-dim . "#f2f2f2")
  (bg-alt . "#e8e8e8")
  (bg-hl-line . "#eaeaef")
  (bg-active . "#e0e0e0")
  (bg-inactive . "#e6e6e6")
  (bg-region . "#b5b5b5")
  (bg-header . "#e4e4e4")
  (bg-tab-active . "#f5f5f5")
  (bg-tab-inactive . "#c0c0c0"))
@end lisp

With those in place, one can use @kbd{M-x my-modus-themes-tinted}
and then load the Modus theme of their choice.  The new palette subset
will come into effect: subtle ocher tints (or shades of gray) for Modus
Operandi and night sky blue shades for Modus Vivendi.  Switching between
the two themes, such as with @kbd{M-x modus-themes-toggle} will
also use the overrides.

Given that this is a user-level customization, one is free to implement
whatever color values they desire, even if the possible combinations
fall below the minimum 7:1 contrast ratio that governs the design of the
themes (the WCAG AAA legibility standard).  Alternatively, this can also
be done programmatically (@ref{Override color saturation}).

The above are expanded into a fully fledged derivative elsewhere in this
document (@ref{Override colors completely}).

For manual interventions it is advised to inspect the source code of
@code{modus-themes-operandi-colors} and @code{modus-themes-vivendi-colors} for the
inline commentary: it explains what the intended use of each palette
subset is.

Furthermore, users may benefit from the @code{modus-themes-contrast} function
that we provide: @ref{Measure color contrast, , test color combinations}.  It measures the contrast
ratio between two color values, so it can help in overriding the palette
(or a subset thereof) without making the end result inaccessible.

@node Override color saturation
@section Override color saturation

@cindex Change a theme's color saturation

In the previous section we documented how one can override color values
manually (@ref{Override colors}).  Here we use a programmatic approach which
leverages the built-in @code{color-saturate-name} function to adjust the
saturation of all color values used by the active Modus theme.  Our goal
is to prepare a counterpart of the active theme's palette that holds
modified color values, adjusted for a percent change in saturation.  A
positive number amplifies the effect, while a negative one will move
towards a grayscale spectrum.

We start with a function that can be either called from Lisp or invoked
interactively.  In the former scenario, we pass to it the rate of change
we want.  While in the latter, a minibuffer prompt asks for a number to
apply the desired effect.  In either case, we intend to assign anew the
value of @code{modus-themes-operandi-color-overrides} (light theme) and the
same for @code{modus-themes-vivendi-color-overrides} (dark theme).

@lisp
(defun my-modus-themes-saturate (percent)
  "Saturate current Modus theme palette overrides by PERCENT."
  (interactive
   (list (read-number "Saturation by percent: ")))
  (let* ((theme (modus-themes--current-theme))
         (palette (pcase theme
                    ('modus-operandi modus-themes-operandi-colors)
                    ('modus-vivendi modus-themes-vivendi-colors)
                    (_ (error "No Modus theme is active"))))
         (overrides (pcase theme
                      ('modus-operandi 'modus-themes-operandi-color-overrides)
                      ('modus-vivendi 'modus-themes-vivendi-color-overrides)
                      (_ (error "No Modus theme is active")))))
    (let (name cons colors)
      (dolist (cons palette)
        (setq name (color-saturate-name (cdr cons) percent))
        (setq name (format "%s" name))
        (setq cons `(,(car cons) . ,name))
        (push cons colors))
      (set overrides colors))
    (pcase theme
      ('modus-operandi (modus-themes-load-operandi))
      ('modus-vivendi (modus-themes-load-vivendi)))))

;; sample Elisp calls (or call `my-modus-themes-saturate' interactively)
(my-modus-themes-saturate 50)
(my-modus-themes-saturate -75)
@end lisp

Using the above has an immediate effect, as it reloads the active Modus
theme.

The @samp{my-modus-themes-saturate} function stores new color values in the
variables @code{modus-themes-operandi-color-overrides} and
@code{modus-themes-vivendi-color-overrides}, meaning that it undoes changes
implemented by the user on individual colors.  To have both automatic
saturation adjustment across the board and retain per-case edits to the
palette, some tweaks to the above function are required.  For example:

@lisp
(defvar my-modus-themes-vivendi-extra-color-overrides
  '((fg-main . "#ead0c0")
    (bg-main . "#050515"))
  "My bespoke colors for `modus-vivendi'.")

(defvar my-modus-themes-operandi-extra-color-overrides
  '((fg-main . "#1a1a1a")
    (bg-main . "#fefcf4"))
  "My bespoke colors for `modus-operandi'.")

(defun my-modus-themes-saturate (percent)
  "Saturate current Modus theme palette overrides by PERCENT.
Preserve the color values stored in
`my-modus-themes-operandi-extra-color-overrides',
`my-modus-themes-vivendi-extra-color-overrides'."
  (interactive
   (list (read-number "Saturation by percent: ")))
  (let* ((theme (modus-themes--current-theme))
         (palette (pcase theme
                    ('modus-operandi modus-themes-operandi-colors)
                    ('modus-vivendi modus-themes-vivendi-colors)
                    (_ (error "No Modus theme is active"))))
         (overrides (pcase theme
                      ('modus-operandi 'modus-themes-operandi-color-overrides)
                      ('modus-vivendi 'modus-themes-vivendi-color-overrides)
                      (_ (error "No Modus theme is active"))))
         (extra-overrides (pcase theme
                            ('modus-operandi my-modus-themes-operandi-extra-color-overrides)
                            ('modus-vivendi my-modus-themes-vivendi-extra-color-overrides)
                            (_ (error "No Modus theme is active")))))
    (let (name cons colors)
      (dolist (cons palette)
        (setq name (color-saturate-name (cdr cons) percent))
        (setq name (format "%s" name))
        (setq cons `(,(car cons) . ,name))
        (push cons colors))
      (set overrides (append extra-overrides colors)))
    (pcase theme
      ('modus-operandi (modus-themes-load-operandi))
      ('modus-vivendi (modus-themes-load-vivendi)))))
@end lisp

To disable the effect, one must reset the aforementioned variables of
the themes to @code{nil}.  Or specify a command for it, such as by taking
inspiration from the @code{modus-themes-toggle} we already provide:

@lisp
(defun my-modus-themes-revert-overrides ()
  "Reset palette overrides and reload active Modus theme."
  (interactive)
  (setq modus-themes-operandi-color-overrides nil
        modus-themes-vivendi-color-overrides nil)
  (pcase (modus-themes--current-theme)
    ('modus-operandi (modus-themes-load-operandi))
    ('modus-vivendi (modus-themes-load-vivendi))))
@end lisp

@node Override colors through blending
@section Override colors through blending

@cindex Change theme colors through blending

This is yet another method of overriding color values.

@ref{Override colors}.

@ref{Override color saturation}.

Building on ideas and concepts from the previous sections, this method
blends the entire palette at once with the chosen colors.  The function
@code{my-modus-themes-interpolate} blends two colors, taking a value from the
themes and mixing it with a user-defined color to arrive at a midpoint.
This scales to all background and foreground colors with the help of the
@code{my-modus-themes-tint-palette} function.

@lisp
(setq my-modus-operandi-bg-blend "#fbf1c7"
      my-modus-operandi-fg-blend "#3a6084"
      my-modus-vivendi-bg-blend "#3a4042"
      my-modus-vivendi-fg-blend "#d7b765")

;; Adapted from the `kurecolor-interpolate' function of kurecolor.el
(defun my-modus-themes-interpolate (color1 color2)
  (cl-destructuring-bind (r g b)
      (mapcar #'(lambda (n) (* (/ n 2) 255.0))
              (cl-mapcar '+ (color-name-to-rgb color1) (color-name-to-rgb color2)))
    (format "#%02X%02X%02X" r g b)))

(defun my-modus-themes-tint-palette (palette bg-blend fg-blend)
  "Modify Modus PALETTE programmatically and return a new palette.
Blend background colors with BG-BLEND and foreground colors with FG-BLEND."
  (let (name cons colors)
    (dolist (cons palette)
      (let ((blend (if (string-match "bg" (symbol-name (car cons)))
                       bg-blend
                     fg-blend)))
        (setq name (my-modus-themes-interpolate (cdr cons) blend)))
      (setq name (format "%s" name))
      (setq cons `(,(car cons) . ,name))
      (push cons colors))
    colors))

(define-minor-mode modus-themes-tinted-mode
  "Tweak some Modus themes colors."
  :init-value nil
  :global t
  (if modus-themes-tinted-mode
      (setq modus-themes-operandi-color-overrides
            (my-modus-themes-tint-palette modus-themes-operandi-colors
                                          my-modus-operandi-bg-blend
                                          my-modus-operandi-fg-blend)
            modus-themes-vivendi-color-overrides
            (my-modus-themes-tint-palette modus-themes-vivendi-colors
                                          my-modus-vivendi-bg-blend
                                          my-modus-vivendi-fg-blend))
    (setq modus-themes-operandi-color-overrides nil
          modus-themes-vivendi-color-overrides nil)))

(modus-themes-tinted-mode 1)
@end lisp

@node Override colors completely
@section Override colors completely

Based on the ideas we have already covered in these sections, the
following code block provides a complete, bespoke pair of color palettes
which override the defaults.  They are implemented as a minor mode, as
explained before (@ref{Override colors}).  We call them ``Summertime'' for
convenience.

@lisp
;; Read the relevant blog post:
;; <https://protesilaos.com/codelog/2022-07-26-modus-themes-color-override-demo/>
(define-minor-mode modus-themes-summertime
  "Refashion the Modus themes by overriding their colors.

This is a complete technology demonstration to show how to
manually override the colors of the Modus themes.  I have taken
good care of those overrides to make them work as a fully fledged
color scheme that is compatible with all user options of the
Modus themes.

These overrides are usable by those who (i) like something more
fancy than the comparatively austere looks of the Modus themes,
and (ii) can cope with a lower contrast ratio.

The overrides are set up as a minor mode, so that the user can
activate the effect on demand.  Those who want to load the
overrides at all times can either add them directly to their
configuration or enable `modus-themes-summertime' BEFORE loading
either of the Modus themes (if the overrides are evaluated after
the theme, the theme must be reloaded).

Remember that all changes to theme-related variables require a
reload of the theme to take effect (the Modus themes have lots of
user options, apart from those overrides).

The `modus-themes-summertime' IS NOT an official extension to the
Modus themes and DOES NOT comply with its lofty accessibility
standards.  It is included in the official manual as guidance for
those who want to make use of the color overriding facility we
provide."
  :init-value nil
  :global t
  (if modus-themes-summertime
      (setq modus-themes-operandi-color-overrides
            '((bg-main . "#fff0f2")
              (bg-dim . "#fbe6ef")
              (bg-alt . "#f5dae6")
              (bg-hl-line . "#fad8e3")
              (bg-active . "#efcadf")
              (bg-inactive . "#f3ddef")
              (bg-active-accent . "#ffbbef")
              (bg-region . "#dfc5d1")
              (bg-region-accent . "#efbfef")
              (bg-region-accent-subtle . "#ffd6ef")
              (bg-header . "#edd3e0")
              (bg-tab-active . "#ffeff2")
              (bg-tab-inactive . "#f8d3ef")
              (bg-tab-inactive-accent . "#ffd9f5")
              (bg-tab-inactive-alt . "#e5c0d5")
              (bg-tab-inactive-alt-accent . "#f3cce0")
              (fg-main . "#543f78")
              (fg-dim . "#5f476f")
              (fg-alt . "#7f6f99")
              (fg-unfocused . "#8f6f9f")
              (fg-active . "#563068")
              (fg-inactive . "#8a5698")
              (fg-docstring . "#5f5fa7")
              (fg-comment-yellow . "#a9534f")
              (fg-escape-char-construct . "#8b207f")
              (fg-escape-char-backslash . "#a06d00")
              (bg-special-cold . "#d3e0f4")
              (bg-special-faint-cold . "#e0efff")
              (bg-special-mild . "#c4ede0")
              (bg-special-faint-mild . "#e0f0ea")
              (bg-special-warm . "#efd0c4")
              (bg-special-faint-warm . "#ffe4da")
              (bg-special-calm . "#f0d3ea")
              (bg-special-faint-calm . "#fadff9")
              (fg-special-cold . "#405fb8")
              (fg-special-mild . "#407f74")
              (fg-special-warm . "#9d6f4f")
              (fg-special-calm . "#af509f")
              (bg-completion . "#ffc5e5")
              (bg-completion-subtle . "#f7cfef")
              (red . "#ed2f44")
              (red-alt . "#e0403d")
              (red-alt-other . "#e04059")
              (red-faint . "#ed4f44")
              (red-alt-faint . "#e0603d")
              (red-alt-other-faint . "#e06059")
              (green . "#217a3c")
              (green-alt . "#417a1c")
              (green-alt-other . "#006f3c")
              (green-faint . "#318a4c")
              (green-alt-faint . "#518a2c")
              (green-alt-other-faint . "#20885c")
              (yellow . "#b06202")
              (yellow-alt . "#a95642")
              (yellow-alt-other . "#a06f42")
              (yellow-faint . "#b07232")
              (yellow-alt-faint . "#a96642")
              (yellow-alt-other-faint . "#a08042")
              (blue . "#275ccf")
              (blue-alt . "#475cc0")
              (blue-alt-other . "#3340ef")
              (blue-faint . "#476ce0")
              (blue-alt-faint . "#575ccf")
              (blue-alt-other-faint . "#3f60d7")
              (magenta . "#bf317f")
              (magenta-alt . "#d033c0")
              (magenta-alt-other . "#844fe4")
              (magenta-faint . "#bf517f")
              (magenta-alt-faint . "#d053c0")
              (magenta-alt-other-faint . "#846fe4")
              (cyan . "#007a9f")
              (cyan-alt . "#3f709f")
              (cyan-alt-other . "#107f7f")
              (cyan-faint . "#108aaf")
              (cyan-alt-faint . "#3f80af")
              (cyan-alt-other-faint . "#3088af")
              (red-active . "#cd2f44")
              (green-active . "#116a6c")
              (yellow-active . "#993602")
              (blue-active . "#475ccf")
              (magenta-active . "#7f2ccf")
              (cyan-active . "#007a8f")
              (red-nuanced-bg . "#ffdbd0")
              (red-nuanced-fg . "#ed6f74")
              (green-nuanced-bg . "#dcf0dd")
              (green-nuanced-fg . "#3f9a4c")
              (yellow-nuanced-bg . "#fff3aa")
              (yellow-nuanced-fg . "#b47232")
              (blue-nuanced-bg . "#e3e3ff")
              (blue-nuanced-fg . "#201f6f")
              (magenta-nuanced-bg . "#fdd0ff")
              (magenta-nuanced-fg . "#c0527f")
              (cyan-nuanced-bg . "#dbefff")
              (cyan-nuanced-fg . "#0f3f60")
              (bg-diff-heading . "#b7cfe0")
              (fg-diff-heading . "#041645")
              (bg-diff-added . "#d6f0d6")
              (fg-diff-added . "#004520")
              (bg-diff-changed . "#fcefcf")
              (fg-diff-changed . "#524200")
              (bg-diff-removed . "#ffe0ef")
              (fg-diff-removed . "#891626")
              (bg-diff-refine-added . "#84cfa4")
              (fg-diff-refine-added . "#002a00")
              (bg-diff-refine-changed . "#cccf8f")
              (fg-diff-refine-changed . "#302010")
              (bg-diff-refine-removed . "#da92b0")
              (fg-diff-refine-removed . "#500010")
              (bg-diff-focus-added . "#a6e5c6")
              (fg-diff-focus-added . "#002c00")
              (bg-diff-focus-changed . "#ecdfbf")
              (fg-diff-focus-changed . "#392900")
              (bg-diff-focus-removed . "#efbbcf")
              (fg-diff-focus-removed . "#5a0010"))
            modus-themes-vivendi-color-overrides
            '((bg-main . "#25152a")
              (bg-dim . "#2a1930")
              (bg-alt . "#382443")
              (bg-hl-line . "#332650")
              (bg-active . "#463358")
              (bg-inactive . "#2d1f3a")
              (bg-active-accent . "#50308f")
              (bg-region . "#5d4a67")
              (bg-region-accent . "#60509f")
              (bg-region-accent-subtle . "#3f285f")
              (bg-header . "#3a2543")
              (bg-tab-active . "#26162f")
              (bg-tab-inactive . "#362647")
              (bg-tab-inactive-accent . "#36265a")
              (bg-tab-inactive-alt . "#3e2f5a")
              (bg-tab-inactive-alt-accent . "#3e2f6f")
              (fg-main . "#debfe0")
              (fg-dim . "#d0b0da")
              (fg-alt . "#ae85af")
              (fg-unfocused . "#8e7f9f")
              (fg-active . "#cfbfef")
              (fg-inactive . "#b0a0c0")
              (fg-docstring . "#c8d9f7")
              (fg-comment-yellow . "#cf9a70")
              (fg-escape-char-construct . "#ff75aa")
              (fg-escape-char-backslash . "#dbab40")
              (bg-special-cold . "#2a3f58")
              (bg-special-faint-cold . "#1e283f")
              (bg-special-mild . "#0f3f31")
              (bg-special-faint-mild . "#0f281f")
              (bg-special-warm . "#44331f")
              (bg-special-faint-warm . "#372213")
              (bg-special-calm . "#4a314f")
              (bg-special-faint-calm . "#3a223f")
              (fg-special-cold . "#c0b0ff")
              (fg-special-mild . "#bfe0cf")
              (fg-special-warm . "#edc0a6")
              (fg-special-calm . "#ff9fdf")
              (bg-completion . "#502d70")
              (bg-completion-subtle . "#451d65")
              (red . "#ff5f6f")
              (red-alt . "#ff8f6d")
              (red-alt-other . "#ff6f9d")
              (red-faint . "#ffa0a0")
              (red-alt-faint . "#f5aa80")
              (red-alt-other-faint . "#ff9fbf")
              (green . "#51ca5c")
              (green-alt . "#71ca3c")
              (green-alt-other . "#51ca9c")
              (green-faint . "#78bf78")
              (green-alt-faint . "#99b56f")
              (green-alt-other-faint . "#88bf99")
              (yellow . "#f0b262")
              (yellow-alt . "#f0e242")
              (yellow-alt-other . "#d0a272")
              (yellow-faint . "#d2b580")
              (yellow-alt-faint . "#cabf77")
              (yellow-alt-other-faint . "#d0ba95")
              (blue . "#778cff")
              (blue-alt . "#8f90ff")
              (blue-alt-other . "#8380ff")
              (blue-faint . "#82b0ec")
              (blue-alt-faint . "#a0acef")
              (blue-alt-other-faint . "#80b2f0")
              (magenta . "#ff70cf")
              (magenta-alt . "#ff77f0")
              (magenta-alt-other . "#ca7fff")
              (magenta-faint . "#e0b2d6")
              (magenta-alt-faint . "#ef9fe4")
              (magenta-alt-other-faint . "#cfa6ff")
              (cyan . "#30cacf")
              (cyan-alt . "#60caff")
              (cyan-alt-other . "#40b79f")
              (cyan-faint . "#90c4ed")
              (cyan-alt-faint . "#a0bfdf")
              (cyan-alt-other-faint . "#a4d0bb")
              (red-active . "#ff6059")
              (green-active . "#64dc64")
              (yellow-active . "#ffac80")
              (blue-active . "#4fafff")
              (magenta-active . "#cf88ff")
              (cyan-active . "#50d3d0")
              (red-nuanced-bg . "#440a1f")
              (red-nuanced-fg . "#ffcccc")
              (green-nuanced-bg . "#002904")
              (green-nuanced-fg . "#b8e2b8")
              (yellow-nuanced-bg . "#422000")
              (yellow-nuanced-fg . "#dfdfb0")
              (blue-nuanced-bg . "#1f1f5f")
              (blue-nuanced-fg . "#bfd9ff")
              (magenta-nuanced-bg . "#431641")
              (magenta-nuanced-fg . "#e5cfef")
              (cyan-nuanced-bg . "#042f49")
              (cyan-nuanced-fg . "#a8e5e5")
              (bg-diff-heading . "#304466")
              (fg-diff-heading . "#dae7ff")
              (bg-diff-added . "#0a383a")
              (fg-diff-added . "#94ba94")
              (bg-diff-changed . "#2a2000")
              (fg-diff-changed . "#b0ba9f")
              (bg-diff-removed . "#50163f")
              (fg-diff-removed . "#c6adaa")
              (bg-diff-refine-added . "#006a46")
              (fg-diff-refine-added . "#e0f6e0")
              (bg-diff-refine-changed . "#585800")
              (fg-diff-refine-changed . "#ffffcc")
              (bg-diff-refine-removed . "#952838")
              (fg-diff-refine-removed . "#ffd9eb")
              (bg-diff-focus-added . "#1d4c3f")
              (fg-diff-focus-added . "#b4dfb4")
              (bg-diff-focus-changed . "#424200")
              (fg-diff-focus-changed . "#d0daaf")
              (bg-diff-focus-removed . "#6f0f39")
              (fg-diff-focus-removed . "#eebdba")))
    (setq modus-themes-operandi-color-overrides nil
          modus-themes-vivendi-color-overrides nil)))
@end lisp

@node Font configurations for Org and others
@section Font configurations for Org and others

@cindex Font configurations

The themes are designed to optionally cope well with mixed font
configurations.  This mostly concerns @code{org-mode} and @code{markdown-mode}, though
expect to find it elsewhere like in @code{Info-mode}.

@ref{Mixed fonts, , Option for font mixing}.

In practice it means that the user can safely opt for a more
prose-friendly proportionately spaced typeface as their default, while
spacing-sensitive elements like tables and inline code always use a
monospaced font, by inheriting from the @code{fixed-pitch} face.

Users can try the built-in @kbd{M-x variable-pitch-mode} to see the
effect in action.

To make everything use your desired font families, you need to configure
the @code{variable-pitch} (proportional spacing) and @code{fixed-pitch} (monospaced)
faces respectively.  It may also be convenient to set your main typeface
by configuring the @code{default} face the same way.

[ The @samp{fontaine} package on GNU ELPA (by the author of the modus-themes)
  is designed to handle this case. ]

Put something like this in your initialization file (also consider
reading the doc string of @code{set-face-attribute}):

@lisp
;; Main typeface
(set-face-attribute 'default nil :family "DejaVu Sans Mono" :height 110)

;; Proportionately spaced typeface
(set-face-attribute 'variable-pitch nil :family "DejaVu Serif" :height 1.0)

;; Monospaced typeface
(set-face-attribute 'fixed-pitch nil :family "DejaVu Sans Mono" :height 1.5)
@end lisp

Or employ the @code{face-attribute} function to read an existing value, such as
if you want to make @code{fixed-pitch} use the font family of the @code{default} face:

@lisp
(set-face-attribute 'fixed-pitch nil :family (face-attribute 'default :family))
@end lisp

The next section shows how to make those work in a more elaborate setup
that is robust to changes between the Modus themes.

@ref{Configure bold and italic faces}.

Note the differences in the @code{:height} property.  The @code{default} face must
specify an absolute value, which is the point size × 10.  So if you want
to use a font at point size @samp{11}, you set the height to @samp{110}.@footnote{ @code{:height}
values do not need to be rounded to multiples of ten: the likes of @samp{115}
are perfectly valid—some typefaces will change to account for those
finer increments.}  Whereas every other face must either not specify a
height or have a value that is relative to the default, represented as a
floating point.  If you use an integer, then that means an absolute
height.  This is of paramount importance: it ensures that all fonts can
scale gracefully when using something like the @code{text-scale-adjust} command
which only operates on the base font size (i.e. the @code{default} face's
absolute height).

@ref{Note on SHR fonts, , Note for EWW and Elfeed fonts}.

@node Configure bold and italic faces
@section Configure bold and italic faces

@cindex Bold and italic fonts

The Modus themes do not hardcode a @code{:weight} or @code{:slant} attribute in the
thousands of faces they cover.  Instead, they configure the generic
faces called @code{bold} and @code{italic} to use the appropriate styles and then
instruct all relevant faces that require emphasis to inherit from them.

This practically means that users can change the particularities of what
it means for a construct to be bold/italic, by tweaking the @code{bold} and
@code{italic} faces.  Cases where that can be useful include:

@itemize
@item
The default typeface does not have a variant with slanted glyphs
(e.g. Fira Mono/Code as of this writing on 2021-07-07), so the user
wants to add another family for the italics, such as Hack.

@item
The typeface of choice provides a multitude of weights and the user
prefers the light one by default.  To prevent the bold weight from
being too heavy compared to the light one, they opt to make @code{bold} use a
semibold weight.

@item
The typeface distinguishes between oblique and italic forms by
providing different font variants (the former are just slanted
versions of the upright forms, while the latter have distinguishing
features as well).  In this case, the user wants to specify the font
that applies to the @code{italic} face.
@end itemize

To achieve those effects, one must first be sure that the fonts they use
have support for those features.  It then is a matter of following the
instructions for all typeface tweaks.

@ref{Font configurations for Org and others}.

In this example, we set the default font family to Fira Code, while we
choose to render italics in the Hack typeface (obviously you need to
pick fonts that work well together):

@lisp
(set-face-attribute 'default nil :family "Fira Code" :height 110)
(set-face-attribute 'italic nil :family "Hack")
@end lisp

And here we play with different weights, using Source Code Pro:

@lisp
(set-face-attribute 'default nil :family "Source Code Pro" :height 110 :weight 'light)
(set-face-attribute 'bold nil :weight 'semibold)
@end lisp

To reset the font family, one can use this:

@lisp
(set-face-attribute 'italic nil :family 'unspecified)
@end lisp

To ensure that the effects persist after switching between the Modus
themes (such as with @kbd{M-x modus-themes-toggle}), the user needs to
write their configurations to a function and pass it to the
@code{modus-themes-after-load-theme-hook}.  This is necessary because themes
set the styles of faces upon activation, overriding prior values where
conflicts occur between the previous and the current states (otherwise
changing themes would not be possible).

@ref{A theme-agnostic hook for theme loading}.

This is a minimal setup to preserve font configurations across theme
load phases.  For a more permanent setup, it is better to rely on the
@code{custom-set-faces} function: @code{set-face-attribute} works just fine, though it
probably is better suited for quick previews or for smaller scale
operations (@code{custom-set-faces} follows the format used in the source code
of the themes, which can make it easier to redefine faces in bulk).

@lisp
;; our generic function
(defun my-modes-themes-bold-italic-faces ()
  (set-face-attribute 'default nil :family "Source Code Pro" :height 110)
  (set-face-attribute 'bold nil :weight 'semibold))

;; or use this if you configure a lot of face and attributes and
;; especially if you plan to use `modus-themes-with-colors', as shown
;; elsewhere in the manual
(defun my-modes-themes-bold-italic-faces ()
  (custom-set-faces
   '(default ((t :family "Source Code Pro" :height 110)))
   '(bold ((t :weight semibold)))))

;; and here is the hook
(add-hook 'modus-themes-after-load-theme-hook #'my-modes-themes-bold-italic-faces)
@end lisp

@ref{Face specs at scale using the themes' palette}.

@node Custom Org todo keyword and priority faces
@section Custom Org todo keyword and priority faces

@cindex Org custom todo faces

Users of @code{org-mode} have the option to configure various keywords and
priority cookies to better match their workflow.  User options are
@code{org-todo-keyword-faces} and @code{org-priority-faces}.

As those are meant to be custom faces, it is futile to have the themes
guess what each user wants to use, which keywords to target, and so on.
Instead, we can provide guidelines on how to customize things to one's
liking with the intent of retaining the overall aesthetic of the themes.

Please bear in mind that the end result of those is not controlled by
the active Modus theme but by how Org maps faces to its constructs.
Editing those while @code{org-mode} is active requires re-initialization of the
mode with @kbd{M-x org-mode-restart} for changes to take effect.

Let us assume you wish to visually differentiate your keywords.  You
have something like this:

@lisp
(setq org-todo-keywords
      '((sequence "TODO(t)" "|" "DONE(D)" "CANCEL(C)")
        (sequence "MEET(m)" "|" "MET(M)")
        (sequence "STUDY(s)" "|" "STUDIED(S)")
        (sequence "WRITE(w)" "|" "WROTE(W)")))
@end lisp

You could then use a variant of the following to inherit from a face
that uses the styles you want and also to preserve the properties
applied by the @code{org-todo} face (in case there is a difference between the
two):

@lisp
(setq org-todo-keyword-faces
      '(("MEET" . '(bold org-todo))
        ("STUDY" . '(warning org-todo))
        ("WRITE" . '(shadow org-todo))))
@end lisp

This will refashion the keywords you specify, while letting the other
items in @code{org-todo-keywords} use their original styles (which are defined
in the @code{org-todo} and @code{org-done} faces).

If you want back the defaults, try specifying just the @code{org-todo} face:

@lisp
(setq org-todo-keyword-faces
      '(("MEET" . org-todo)
        ("STUDY" . org-todo)
        ("WRITE" . org-todo)))
@end lisp

When you inherit from multiple faces, you need to quote the list as
shown further above.  The order is significant: the first entry is
applied on top of the second, overriding any properties that are
explicitly set for both of them: any property that is not specified is
not overridden, so, for example, if @code{org-todo} has a background and a
foreground, while @code{font-lock-type-face} only has a foreground, the merged
face will include the background of the former and the foreground of the
latter.  If you do not want to blend multiple faces, you do not need a
quoted list.  A pattern of @samp{keyword . face} will suffice.

Both approaches can be used simultaneously, as illustrated in this
configuration of the priority cookies:

@lisp
(setq org-priority-faces
      '((?A . '(bold org-priority))
        (?B . org-priority)
        (?C . '(shadow org-priority))))
@end lisp

To find all the faces that are loaded in your current Emacs session, use
@kbd{M-x list-faces-display}.  Try @kbd{M-x describe-variable} as well and
then specify the name of each of those Org variables demonstrated above.
Their documentation strings will offer you further guidance.

Recall that the themes let you retrieve a color from their palette.  Do
it if you plan to control face attributes.

@ref{Case-by-case face specs using the themes' palette, , Custom face specs using the themes' palette}.

@ref{Measure color contrast, , Check color combinations}.

@node Custom Org emphasis faces
@section Custom Org emphasis faces

@cindex Org custom emphasis faces

Org provides the user option @code{org-emphasis-alist} which associates a
character with a face, list of faces, or face attributes.  The default
specification of that variable looks like this:

@lisp
(setq org-emphasis-alist
      '(("*" bold)
        ("/" italic)
        ("_" underline)
        ("=" org-verbatim verbatim)
        ("~" org-code verbatim)
        ("+" (:strike-through t))))
@end lisp

With the exception of @code{org-verbatim} and @code{org-code} faces, everything else
uses the corresponding type of emphasis: a bold typographic weight, or
italicized, underlined, and struck through text.

The best way for users to add some extra attributes, such as a
foreground color, is to define their own faces and assign them to the
given emphasis marker/character.

This is a custom face that extends the standard @code{bold} face with a red
foreground value (so it colorises the text in addition to the bold
weight):

@lisp
(defface my-org-emphasis-bold
  '((default :inherit bold)
    (((class color) (min-colors 88) (background light))
     :foreground "#a60000")
    (((class color) (min-colors 88) (background dark))
     :foreground "#ff8059"))
  "My bold emphasis for Org.")
@end lisp

This face definition reads as follows:

@itemize
@item
Always inherit the @code{bold} face (@ref{Configure bold and italic faces}).
@item
For versions of Emacs that support at least 88 colors (graphical
Emacs, for example) and use a light background, apply the @samp{#a60000}
value.
@item
For the same kind of Emacs that has a dark background use the @samp{#ff8059}
color instead.
@end itemize

Same principle for how to extend @code{italic} and @code{underline} with, for example,
green and yellow hues, respectively:

@lisp
(defface my-org-emphasis-italic
  '((default :inherit italic)
    (((class color) (min-colors 88) (background light))
     :foreground "#005e00")
    (((class color) (min-colors 88) (background dark))
     :foreground "#44bc44"))
  "My italic emphasis for Org.")

(defface my-org-emphasis-underline
  '((default :inherit underline)
    (((class color) (min-colors 88) (background light))
     :foreground "#813e00")
    (((class color) (min-colors 88) (background dark))
     :foreground "#d0bc00"))
  "My underline emphasis for Org.")
@end lisp

In the case of a strike-through effect, we have no generic face to
inherit from, so we can write it as follows to also change the
foreground to a more subtle gray:

@lisp
(defface my-org-emphasis-strike-through
  '((default :strike-through t)
    (((class color) (min-colors 88) (background light))
     :foreground "#505050")
    (((class color) (min-colors 88) (background dark))
     :foreground "#a8a8a8"))
  "My strike-through emphasis for Org.")
@end lisp

Or we can just change the color of the line that strikes through the
text to, for example, a shade of red:

@lisp
(defface my-org-emphasis-strike-through
  '((((class color) (min-colors 88) (background light))
     :strike-through "#972500")
    (((class color) (min-colors 88) (background dark))
     :strike-through "#ef8b50"))
  "My strike-through emphasis for Org.")
@end lisp

It is possible to combine those effects:

@lisp
(defface my-org-emphasis-strike-through
  '((((class color) (min-colors 88) (background light))
     :strike-through "#972500" :foreground "#505050")
    (((class color) (min-colors 88) (background dark))
     :strike-through "#ef8b50" :foreground "#a8a8a8"))
  "My strike-through emphasis for Org.")
@end lisp

One may inspect the variables @code{modus-themes-operandi-colors} and
@code{modus-themes-vivendi-colors} for possible color values.  Or call the
command @code{modus-themes-list-colors} to show a buffer that previews each
entry in the palette.

@ref{Visualize the active Modus theme's palette}.

Once we have defined the faces we need, we must update the
@code{org-emphasis-alist}.  Given that @code{org-verbatim} and @code{org-code} are already
styled by the themes, it probably is best not to edit them:

@lisp
(setq org-emphasis-alist
      '(("*" my-org-emphasis-bold)
        ("/" my-org-emphasis-italic)
        ("_" my-org-emphasis-underline)
        ("=" org-verbatim verbatim)
        ("~" org-code verbatim)
        ("+" my-org-emphasis-strike-through)))
@end lisp

That's it!  For changes to take effect in already visited Org files,
invoke @kbd{M-x org-mode-restart}.

@node Update Org block delimiter fontification
@section Update Org block delimiter fontification

As noted in the section about @code{modus-themes-org-blocks}, Org contains a
variable that determines whether the block's begin and end lines are
extended to the edge of the window (@ref{Org mode blocks, , Option for org-mode block styles}).
The variable is @code{org-fontify-whole-block-delimiter-line}.

Users who change the style of Org blocks from time to time may prefer to
automatically update delimiter line fontification, such as with the
following setup:

@lisp
(defun my-modus-themes-org-fontify-block-delimiter-lines ()
  "Match `org-fontify-whole-block-delimiter-line' to theme style.
Run this function at the post theme load phase, such as with the
`modus-themes-after-load-theme-hook'."
  (if (eq modus-themes-org-blocks 'gray-background)
      (setq org-fontify-whole-block-delimiter-line t)
    (setq org-fontify-whole-block-delimiter-line nil)))

(add-hook 'modus-themes-after-load-theme-hook
          #'my-modus-themes-org-fontify-block-delimiter-lines)
@end lisp

Then @kbd{M-x org-mode-restart} for changes to take effect, though manual
intervention can be circumvented by tweaking the function thus:

@lisp
(defun my-modus-themes-org-fontify-block-delimiter-lines ()
  "Match `org-fontify-whole-block-delimiter-line' to theme style.
Run this function at the post theme load phase, such as with the
`modus-themes-after-load-theme-hook'."
  (if (eq modus-themes-org-blocks 'gray-background)
      (setq org-fontify-whole-block-delimiter-line t)
    (setq org-fontify-whole-block-delimiter-line nil))
  (when (derived-mode-p 'org-mode)
    (font-lock-flush)))
@end lisp

@node Measure color contrast
@section Measure color contrast

@findex modus-themes-contrast
@findex modus-themes-wcag-formula
@cindex Color contrast

The themes provide the functions @code{modus-themes-wcag-formula} and
@code{modus-themes-contrast}.  The former is a direct implementation of the
WCAG formula: @uref{https://www.w3.org/TR/WCAG20-TECHS/G18.html}.  It
calculates the relative luminance of a color value that is expressed in
hexadecimal RGB notation.  While the latter function is just a
convenient wrapper for comparing the relative luminance between two
colors.

In practice, one needs to work only with @code{modus-themes-contrast}.  It
accepts two color values and returns their contrast ratio.  Values range
from 1 to 21 (lowest to highest).  The themes are designed to always be
equal or higher than 7 for each combination of background and foreground
that they use (this is the WCAG AAA standard---the most demanding of its
kind).

A couple of examples (rounded numbers):

@lisp
;; Pure white with pure green
(modus-themes-contrast "#ffffff" "#00ff00")
;; => 1.37
;; That is an outright inaccessible combo

;; Pure black with pure green
(modus-themes-contrast "#000000" "#00ff00")
;; => 15.3
;; That is a highly accessible combo
@end lisp

It does not matter which color value comes first.  The ratio is always
the same.

If one does not wish to read all the decimal points, it is possible to
try something like this:

@lisp
(format "%0.2f" (modus-themes-contrast "#000000" "#00ff00"))
@end lisp

While it is fine to perform such calculations on a case-by-case basis,
it is preferable to implement formulas and tables for more demanding
tasks.  Such instruments are provided by @code{org-mode} or @code{orgtbl-mode}, both
of which are built into Emacs.  Below is such a table that derives the
contrast ratio of all colors in the first column (pure red, green, blue)
relative to the color specified in the first row of the second column
(pure white) and rounds the results:

@example
|         | #ffffff |
|---------+---------|
| #ff0000 |    4.00 |
| #00ff00 |    1.37 |
| #0000ff |    8.59 |
#+tblfm: $2='(modus-themes-contrast $1 @@1$2);%0.2f
@end example

To measure color contrast one needs to start from a known value.  This
typically is the background.  The Modus themes define an expanded
palette in large part because certain colors are only meant to be used
in combination with some others.  Consult the source code for the
minutia and relevant commentary.

Such knowledge may prove valuable while attempting to override some of
the themes' colors: @ref{Override colors}.

@node Load theme depending on time of day
@section Load theme depending on time of day

While we do provide @code{modus-themes-toggle} to manually switch between the
themes, users may also set up their system to perform such a task
automatically at sunrise and sunset.

This can be accomplished by specifying the coordinates of one's location
using the built-in @file{solar.el} and then configuring the @samp{circadian}
package:

@lisp
(use-package solar                      ; built-in
  :config
  (setq calendar-latitude 35.17
        calendar-longitude 33.36))

(use-package circadian                  ; you need to install this
  :ensure
  :after solar
  :config
  (setq circadian-themes '((:sunrise . modus-operandi)
                           (:sunset  . modus-vivendi)))
  (circadian-setup))
@end lisp

@node Backdrop for pdf-tools
@section Backdrop for pdf-tools

@cindex Remapping pdf-tools backdrop

Most PDF files use a white background for their page, making it
impossible to discern the file's boundaries in the buffer while using
the Modus Operandi theme.  To introduce a distinction between the
buffer's backdrop and the PDF page's background, the former must be
rendered as some shade of gray.  Ideally, @code{pdf-tools} would provide a face
that the themes could support directly, though this does not seem to be
the case for the time being.  We must thus employ the face remapping
technique that is documented elsewhere in this document to change the
buffer-local value of the @code{default} face.

@ref{Remap face with local value}.

To remap the buffer's backdrop, we start with a function like this one:

@lisp
(defun my-pdf-tools-backdrop ()
  (face-remap-add-relative
   'default
   `(:background ,(modus-themes-color 'bg-alt))))

(add-hook 'pdf-tools-enabled-hook #'my-pdf-tools-backdrop)
@end lisp

The idea is to assign that function to a hook that gets called when
@code{pdf-tools} renders the document: @code{pdf-tools-enabled-hook}.  This is enough
when you only use one theme.  However it has the downside of setting the
background color value only at render time.  In other words, the face
remapping function does not get evaluated anew whenever the theme
changes, such as upon invoking @kbd{M-x modus-themes-toggle}.

To have our face remapping adapt gracefully while switching between the
Modus themes, we need to also account for the current theme and control
the activation of @code{pdf-view-midnight-minor-mode}.  To which end we arrive
at something like the following, which builds on the above example:

@lisp
(defun my-pdf-tools-backdrop ()
  (face-remap-add-relative
   'default
   `(:background ,(modus-themes-color 'bg-alt))))

(defun my-pdf-tools-midnight-mode-toggle ()
  (when (derived-mode-p 'pdf-view-mode)
    (if (eq (car custom-enabled-themes) 'modus-vivendi)
        (pdf-view-midnight-minor-mode 1)
      (pdf-view-midnight-minor-mode -1))
    (my-pdf-tools-backdrop)))

(defun my-pdf-tools-themes-toggle ()
  (mapc
   (lambda (buf)
     (with-current-buffer buf
       (my-pdf-tools-midnight-mode-toggle)))
   (buffer-list)))

(add-hook 'pdf-tools-enabled-hook #'my-pdf-tools-midnight-mode-toggle)
(add-hook 'modus-themes-after-load-theme-hook #'my-pdf-tools-themes-toggle)
@end lisp

With those in place, PDFs have a distinct backdrop for their page, while
buffers with major-mode as @code{pdf-view-mode} automatically switches to dark
mode when @code{modus-themes-toggle} is called.

@node Decrease mode line height
@section Decrease mode line height

@cindex Decrease mode line height

By default, the mode line of the Modus themes is set to 1 pixel width
for its @samp{:box} attribute.  In contrast, the mode line of stock Emacs is -1
pixel.  This small difference is considered necessary for the purposes
of accessibility as our out-of-the-box design has a prominent color
around the mode line (a border) to make its boundaries clear.  With a
negative width the border and the text on the mode line can feel a bit
more difficult to read under certain scenaria.

Furthermore, the user option @code{modus-themes-mode-line} (@ref{Mode line}) does not
allow for such a negative value because there are many edge cases that
simply make for a counter-intuitive set of possibilities, such as a @samp{0}
value not being acceptable by the underlying face infrastructure, and
negative values greater than @samp{-2} not being particularly usable.

For these reasons, users who wish to decrease the overall height of the
mode line must handle things on their own by implementing the methods
for face customization documented herein.

@ref{Case-by-case face specs using the themes' palette, , Basic face customization}.

One such method is to create a function that configures the desired
faces and hook it to @code{modus-themes-after-load-theme-hook} so that it
persists while switching between the Modus themes with the command
@code{modus-themes-toggle}.

This one simply disables the box altogether, which will reduce the
height of the mode lines, but also remove their border:

@lisp
(defun my-modus-themes-custom-faces ()
  (set-face-attribute 'mode-line nil :box nil)
  (set-face-attribute 'mode-line-inactive nil :box nil))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

The above relies on the @code{set-face-attribute} function, though users who
plan to reuse colors from the theme and do so at scale are better off
with the more streamlined combination of the @code{modus-themes-with-colors}
macro and @code{custom-set-faces}.

@ref{Face specs at scale using the themes' palette, , Face customization at scale}.

As explained before in this document, this approach has a syntax that is
consistent with the source code of the themes, so it probably is easier
to reuse parts of the design.

The following emulates the stock Emacs style, while still using the
colors of the Modus themes (whichever attribute is not explicitly stated
is inherited from the underlying theme):

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(mode-line ((,class :box (:line-width -1 :style released-button))))
     `(mode-line-inactive ((,class :box (:line-width -1 :color ,bg-region)))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

And this one is like the out-of-the-box style of the Modus themes, but
with the -1 height instead of 1:

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(mode-line ((,class :box (:line-width -1 :color ,fg-alt))))
     `(mode-line-inactive ((,class :box (:line-width -1 :color ,bg-region)))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

Finally, to also change the background color of the active mode line,
such as that it looks like the ``accented'' variant which is possible via
the user option @code{modus-themes-mode-line}, the @samp{:background} attribute needs
to be specified as well:

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(mode-line ((,class :box (:line-width -1 :color ,fg-alt) :background ,bg-active-accent)))
     `(mode-line-inactive ((,class :box (:line-width -1 :color ,bg-region)))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

@node Toggle themes without reloading them
@section Toggle themes without reloading them

@cindex Switch themes without load-theme

Users who have a stable setup and who only ever need to toggle between
the themes without triggering a full reload, are better off defining
their own command which calls @code{enable-theme} instead of @code{load-theme}:

@lisp
(defun my-modus-themes-toggle ()
  "Toggle between `modus-operandi' and `modus-vivendi' themes.
This uses `enable-theme' instead of the standard method of
`load-theme'.  The technicalities are covered in the Modus themes
manual."
  (interactive)
  (pcase (modus-themes--current-theme)
    ('modus-operandi (progn (enable-theme 'modus-vivendi)
                            (disable-theme 'modus-operandi)))
    ('modus-vivendi (progn (enable-theme 'modus-operandi)
                            (disable-theme 'modus-vivendi)))
    (_ (error "No Modus theme is loaded; evaluate `modus-themes-load-themes' first"))))
@end lisp

@ref{Differences between loading and enabling}.

Recall that @code{modus-themes-toggle} uses @code{load-theme}.

@node A theme-agnostic hook for theme loading
@section A theme-agnostic hook for theme loading

The themes are designed with the intent to be useful to Emacs users of
varying skill levels, from beginners to experts.  This means that we try
to make things easier by not expecting anyone reading this document to
be proficient in Emacs Lisp or programming in general.

Such a case is with the use of the @code{modus-themes-after-load-theme-hook},
which runs after @code{modus-themes-toggle}, @code{modus-themes-load-operandi}, or
@code{modus-themes-load-vivendi} is evaluated.  We recommend using that hook
for advanced customizations, because (1) we know for sure that it is
available once the themes are loaded, and (2) anyone consulting this
manual, especially the sections on enabling and loading the themes, will
be in a good position to benefit from that hook.

Advanced users who have a need to switch between the Modus themes and
other items will find that such a hook does not meet their requirements:
it only works with the Modus themes and only with the aforementioned
functions.

A theme-agnostic setup can be configured thus:

@lisp
(defvar after-enable-theme-hook nil
   "Normal hook run after enabling a theme.")

(defun run-after-enable-theme-hook (&rest _args)
   "Run `after-enable-theme-hook'."
   (run-hooks 'after-enable-theme-hook))

(advice-add 'enable-theme :after #'run-after-enable-theme-hook)
@end lisp

This creates the @code{after-enable-theme-hook} and makes it run after each
call to @code{enable-theme}, which means that it will work for all themes and
also has the benefit that it does not depend on functions such as
@code{modus-themes-toggle} and the others mentioned above.  @code{enable-theme} is
called internally by @code{load-theme}, so the hook works everywhere.

Now this specific piece of Elisp may be simple for experienced users,
but it is not easy to read for newcomers, including the author of the
Modus themes for the first several months of their time as an Emacs
user.  Hence our hesitation to recommend it as part of the standard
setup of the Modus themes (it is generally a good idea to understand
what the implications are of advising a function).

@node Diffs with only the foreground
@section Diffs with only the foreground

@cindex Foreground-only diffs

Buffers that show differences between versions of a file or buffer, such
as in @code{diff-mode} and @code{ediff} always use color-coded background and
foreground combinations.

@ref{Diffs, , Option for diff buffer looks}.

User may, however, prefer a style that removes the color-coded
backgrounds from regular changes while keeping them for word-wise (aka
``refined'') changes---backgrounds for word-wise diffs are helpful in
context.  To make this happen, one can use the @code{modus-themes-with-colors}
macro (@ref{Face specs at scale using the themes' palette}):

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(modus-themes-diff-added ((,class :background unspecified :foreground ,green))) ; OR ,blue for deuteranopia
     `(modus-themes-diff-changed ((,class :background unspecified :foreground ,yellow)))
     `(modus-themes-diff-removed ((,class :background unspecified :foreground ,red)))

     `(modus-themes-diff-refine-added ((,class :background ,bg-diff-added :foreground ,fg-diff-added)))
     ;; `(modus-themes-diff-refine-added ((,class :background ,bg-diff-added-deuteran :foreground ,fg-diff-added-deuteran)))
     `(modus-themes-diff-refine-changed ((,class :background ,bg-diff-changed :foreground ,fg-diff-changed)))
     `(modus-themes-diff-refine-removed ((,class :background ,bg-diff-removed :foreground ,fg-diff-removed)))

     `(modus-themes-diff-focus-added ((,class :background ,bg-dim :foreground ,green))) ; OR ,blue for deuteranopia
     `(modus-themes-diff-focus-changed ((,class :background ,bg-dim :foreground ,yellow)))
     `(modus-themes-diff-focus-removed ((,class :background ,bg-dim :foreground ,red)))

     `(modus-themes-diff-heading ((,class :background ,bg-alt :foreground ,fg-main)))

     `(diff-indicator-added ((,class :foreground ,green))) ; OR ,blue for deuteranopia
     `(diff-indicator-changed ((,class :foreground ,yellow)))
     `(diff-indicator-removed ((,class :foreground ,red)))

     `(magit-diff-added ((,class :background unspecified :foreground ,green-faint)))
     `(magit-diff-changed ((,class :background unspecified :foreground ,yellow-faint)))
     `(magit-diff-removed ((,class :background unspecified :foreground ,red-faint)))
     `(magit-diff-context-highlight ((,class :background ,bg-dim :foreground ,fg-dim))))))

;; This is so that the changes persist when switching between
;; `modus-operandi' and `modus-vivendi'.
(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

This used to be an optional style of @code{modus-themes-diffs}, but has been
removed since version @samp{2.0.0} to ensure that the accessibility standard
and aesthetic quality of the themes is not compromised.

@node Ediff without diff color-coding
@section Ediff without diff color-coding

Ediff uses the same color-coding as ordinary diffs in @code{diff-mode}, Magit,
etc. (@ref{Diffs, , Option for diff buffer looks}).  This is consistent with the
principle of least surprise.

Users may, however, prefer to treat Ediff differently on the premise
that it does not need any particular color-coding to show added or
removed lines/words: it does not use the @samp{+} or @samp{-} markers, after all.

This can be achieved by customizing the Ediff faces with color
combinations that do not carry the same connotations as those of diffs.
Consider this example, which leverages the @code{modus-themes-with-colors}
macro (@ref{Face specs at scale using the themes' palette}):

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(ediff-current-diff-A ((,class :inherit unspecified :background ,bg-special-faint-cold :foreground ,fg-special-cold)))
     `(ediff-current-diff-B ((,class :inherit unspecified :background ,bg-special-faint-warm :foreground ,fg-special-warm)))
     `(ediff-current-diff-C ((,class :inherit unspecified :background ,bg-special-faint-calm :foreground ,fg-special-calm)))
     `(ediff-fine-diff-A ((,class :inherit unspecified :background ,bg-special-cold :foreground ,fg-special-cold)))
     `(ediff-fine-diff-B ((,class :inherit unspecified :background ,bg-special-warm :foreground ,fg-special-warm)))
     `(ediff-fine-diff-C ((,class :inherit unspecified :background ,bg-special-calm :foreground ,fg-special-calm))))))

;; This is so that the changes persist when switching between
;; `modus-operandi' and `modus-vivendi'.
(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

Remove the @samp{:foreground} and its value to preserve the underlying
coloration.

@ref{Visualize the active Modus theme's palette}.

@node Near-monochrome syntax highlighting
@section Near-monochrome syntax highlighting

@cindex Monochrome code syntax

While the Modus themes do provide a user option to control the overall
style of syntax highlighting in programming major modes, they do not
cover the possibility of a monochromatic or near-monochromatic design
(@ref{Syntax styles, , Option for syntax highlighting}).  This is due to the multitude of
preferences involved: one may like comments to be styled with an accent
value, another may want certain constructs to be bold, a third may apply
italics to doc strings but not comments@dots{}  The possibilities are
virtually endless.  As such, this sort of design is best handled at the
user level in accordance with the information furnished elsewhere in
this manual.

@ref{Case-by-case face specs using the themes' palette}.

@ref{Face specs at scale using the themes' palette}.

The gist is that we want to override the font-lock faces.  For our
changes to persist while switching between @code{modus-operandi} and
@code{modus-vivendi} we wrap our face overrides in a function that we hook to
@code{modus-themes-after-load-theme-hook}.

Users who want to replicate the structure of the themes' source code are
advised to use the examples with @code{custom-set-faces}.  Those who prefer a
different approach can use the snippets which call @code{set-face-attribute}.
Below are the code blocks.

The following uses a yellow accent value for comments and green hues for
strings.  Regexp grouping constructs have color values that work in the
context of a green string.  All other elements use the main foreground
color, except warnings such as the @code{user-error} function in Elisp
buffers which gets a subtle red tint (not to be confused with the
@code{warning} face which is used for genuine warnings).  Furthermore, notice
the @code{modus-themes-bold} and @code{modus-themes-slant} which apply the
preference set in the user options @code{modus-themes-bold-constructs} and
@code{modus-themes-italic-constructs}, respectively.  Users who do not want
this conditionally must replace these faces with @code{bold} and @code{italic}
respectively (or @code{unspecified} to disable the effect altogether).

@lisp
;; This is the hook.  It will not be replicated across all code samples.
(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-subtle-syntax)

(defun my-modus-themes-subtle-syntax ()
  (modus-themes-with-colors
    (custom-set-faces
     `(font-lock-builtin-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-comment-delimiter-face ((,class :inherit font-lock-comment-face)))
     `(font-lock-comment-face ((,class :inherit unspecified :foreground ,fg-comment-yellow)))
     `(font-lock-constant-face ((,class :foreground unspecified)))
     `(font-lock-doc-face ((,class :inherit modus-themes-slant :foreground ,fg-special-mild)))
     `(font-lock-function-name-face ((,class :foreground unspecified)))
     `(font-lock-keyword-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-negation-char-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-preprocessor-face ((,class :foreground unspecified)))
     `(font-lock-regexp-grouping-backslash ((,class :inherit bold :foreground ,yellow)))
     `(font-lock-regexp-grouping-construct ((,class :inherit bold :foreground ,blue-alt-other)))
     `(font-lock-string-face ((,class :foreground ,green-alt-other)))
     `(font-lock-type-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-variable-name-face ((,class :foreground unspecified)))
     `(font-lock-warning-face ((,class :inherit modus-themes-bold :foreground ,red-nuanced-fg))))))

;; Same as above with `set-face-attribute' instead of `custom-set-faces'
(defun my-modus-themes-subtle-syntax ()
  (modus-themes-with-colors
    (set-face-attribute 'font-lock-builtin-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-comment-delimiter-face nil :inherit 'font-lock-comment-face)
    (set-face-attribute 'font-lock-comment-face nil :inherit 'unspecified :foreground fg-comment-yellow)
    (set-face-attribute 'font-lock-constant-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-doc-face nil :inherit 'modus-themes-slant :foreground fg-special-mild)
    (set-face-attribute 'font-lock-function-name-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-keyword-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-negation-char-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-preprocessor-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-regexp-grouping-backslash nil :inherit 'bold :foreground yellow)
    (set-face-attribute 'font-lock-regexp-grouping-construct nil :inherit 'bold :foreground blue-alt-other)
    (set-face-attribute 'font-lock-string-face nil :foreground green-alt-other)
    (set-face-attribute 'font-lock-type-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-variable-name-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-warning-face nil :inherit 'modus-themes-bold :foreground red-nuanced-fg)))
@end lisp

The following sample is the same as above, except strings are blue and
comments are gray.  Regexp constructs are adapted accordingly.

@lisp
(defun my-modus-themes-subtle-syntax ()
  (modus-themes-with-colors
    (custom-set-faces
     `(font-lock-builtin-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-comment-delimiter-face ((,class :inherit font-lock-comment-face)))
     `(font-lock-comment-face ((,class :inherit unspecified :foreground ,fg-alt)))
     `(font-lock-constant-face ((,class :foreground unspecified)))
     `(font-lock-doc-face ((,class :inherit modus-themes-slant :foreground ,fg-docstring)))
     `(font-lock-function-name-face ((,class :foreground unspecified)))
     `(font-lock-keyword-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-negation-char-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-preprocessor-face ((,class :foreground unspecified)))
     `(font-lock-regexp-grouping-backslash ((,class :inherit bold :foreground ,fg-escape-char-backslash)))
     `(font-lock-regexp-grouping-construct ((,class :inherit bold :foreground ,fg-escape-char-construct)))
     `(font-lock-string-face ((,class :foreground ,blue-alt)))
     `(font-lock-type-face ((,class :inherit modus-themes-bold :foreground unspecified)))
     `(font-lock-variable-name-face ((,class :foreground unspecified)))
     `(font-lock-warning-face ((,class :inherit modus-themes-bold :foreground ,red-nuanced-fg))))))

;; Same as above with `set-face-attribute' instead of `custom-set-faces'
(defun my-modus-themes-subtle-syntax ()
  (modus-themes-with-colors
    (set-face-attribute 'font-lock-builtin-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-comment-delimiter-face nil :inherit 'font-lock-comment-face)
    (set-face-attribute 'font-lock-comment-face nil :inherit 'unspecified :foreground fg-alt)
    (set-face-attribute 'font-lock-constant-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-doc-face nil :inherit 'modus-themes-slant :foreground fg-docstring)
    (set-face-attribute 'font-lock-function-name-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-keyword-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-negation-char-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-preprocessor-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-regexp-grouping-backslash nil :inherit 'bold :foreground fg-escape-char-backslash)
    (set-face-attribute 'font-lock-regexp-grouping-construct nil :inherit 'bold :foreground fg-escape-char-construct)
    (set-face-attribute 'font-lock-string-face nil :foreground blue-alt)
    (set-face-attribute 'font-lock-type-face nil :inherit 'modus-themes-bold :foreground 'unspecified)
    (set-face-attribute 'font-lock-variable-name-face nil :foreground 'unspecified)
    (set-face-attribute 'font-lock-warning-face nil :inherit 'modus-themes-bold :foreground red-nuanced-fg)))
@end lisp

@node Custom hl-todo colors
@section Custom hl-todo colors

The @samp{hl-todo} package provides the user option @code{hl-todo-keyword-faces}:
it specifies a pair of keyword and corresponding color value.  The Modus
themes configure that option in the interest of legibility.  While this
works for our purposes, users may still prefer to apply their custom
values, in which case the following approach is necessary:

@lisp
(defun my-modus-themes-hl-todo-faces ()
  (setq hl-todo-keyword-faces '(("TODO" . "#ff0000")
                                ("HACK" . "#ffff00")
                                ("XXX" . "#00ffff")
                                ("NOTE" . "#ff00ff"))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-hl-todo-faces)
@end lisp

Or include a @code{let} form, if needed:

@lisp
(defun my-modus-themes-hl-todo-faces ()
  (let ((red "#ff0000")
        (blue "#0000ff"))
    (setq hl-todo-keyword-faces `(("TODO" . ,blue)
                                  ("HACK" . ,red)
                                  ("XXX" . ,red)
                                  ("NOTE" . ,blue)))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-hl-todo-faces)
@end lisp

Normally, we do not touch user options, though this is an exception:
otherwise the defaults are not always legible.

@node Add support for solaire-mode
@section Add support for solaire-mode

The @samp{solaire-mode} package dims the background of what it considers
ancillary ``UI'' buffers, such as the minibuffer and Dired buffers.  The
Modus themes used to support Solaire on the premise that the user was
(i) opting in to it, (ii) understood why certain buffers were more gray,
and (iii) knew what other adjustments had to be made to prevent broken
visuals (e.g. the default style of the @code{modus-themes-completions} uses a
subtle gray background for the selection, which with Solaire becomes
practically invisible).

However, the assumption that users opt in to this feature does not
always hold true.  There are cases where it is enabled by defaultsuch as
in the popular Doom Emacs configuration.  Thus, the unsuspecting user
who loads @code{modus-operandi} or @code{modus-vivendi} without the requisite
customizations is getting a sub-par experience; an experience that we
did not intend and cannot genuinely fix.

Because the Modus themes are meant to work everywhere, we cannot make an
exception for Doom Emacs and/or Solaire users.  Furthermore, we shall
not introduce hacks, such as by adding a check in all relevant faces to
be adjusted based on Solaire or whatever other package.  Hacks of this
sort are unsustainable and penalize the entire userbase.  Besides, the
themes are built into Emacs and we must keep their standard high.

The fundamental constraint with Solaire is that Emacs does not have a
real distinction between ``content'' and ``UI'' buffers.  For themes to work
with Solaire, they need to be designed around that package.  Such is an
arrangement that compromises on our accessibility standards and/or
hinders our efforts to provide the best possible experience while using
the Modus themes.

As such, @samp{solaire-mode} is not---and will not be---supported by the
Modus themes (or any other of my themes, for that matter).  Users who
want it must style the faces manually.  Below is some sample code, based
on what we cover at length elsewhere in this manual:

@ref{Advanced customization}.

@ref{Face specs at scale using the themes' palette}.

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(solaire-default-face ((,class :inherit default :background ,bg-alt :foreground ,fg-dim)))
     `(solaire-line-number-face ((,class :inherit solaire-default-face :foreground ,fg-unfocused)))
     `(solaire-hl-line-face ((,class :background ,bg-active)))
     `(solaire-org-hide-face ((,class :background ,bg-alt :foreground ,bg-alt))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

As always, re-load the theme for changes to take effect.

@node Face coverage
@chapter Face coverage

The Modus themes try to provide as close to full face coverage as
possible.  This is necessary to ensure a consistently accessible reading
experience across all available interfaces.

@menu
* Supported packages::           Full list of covered face groups
* Indirectly covered packages::
@end menu

@node Supported packages
@section Full support for packages or face groups

@cindex Explicitly supported packages

This list will always be updated to reflect the current state of the
project.  The idea is to offer an overview of the known status of all
affected face groups.  The items with an appended asterisk @samp{*} tend to
have lots of extensions, so the ``full support'' may not be 100% true…

@itemize
@item
ace-window
@item
alert
@item
all-the-icons
@item
all-the-icons-dired
@item
all-the-icons-ibuffer
@item
annotate
@item
ansi-color
@item
anzu
@item
apropos
@item
artbollocks-mode
@item
auctex and @TeX{}
@item
auto-dim-other-buffers
@item
avy
@item
awesome-tray
@item
bbdb
@item
binder
@item
bm
@item
bongo
@item
boon
@item
bookmark
@item
breakpoint (provided by the built-in @file{gdb-mi.el} library)
@item
calendar and diary
@item
calfw
@item
calibredb
@item
centaur-tabs
@item
cfrs
@item
change-log and log-view (such as @code{vc-print-log}, @code{vc-print-root-log})
@item
chart
@item
cider
@item
circe
@item
citar
@item
color-rg
@item
column-enforce-mode
@item
company-mode*
@item
company-posframe
@item
compilation-mode
@item
completions
@item
consult
@item
corfu
@item
corfu-quick
@item
counsel*
@item
counsel-css
@item
cov
@item
cperl-mode
@item
crontab-mode
@item
css-mode
@item
csv-mode
@item
ctrlf
@item
custom (what you get with @kbd{M-x customize})
@item
dap-mode
@item
deadgrep
@item
debbugs
@item
deft
@item
denote
@item
devdocs
@item
dictionary
@item
diff-hl
@item
diff-mode
@item
dim-autoload
@item
dir-treeview
@item
dired
@item
dired-async
@item
dired-git
@item
dired-git-info
@item
dired-narrow
@item
dired-subtree
@item
diredfl
@item
diredp (dired+)
@item
display-fill-column-indicator-mode
@item
doom-modeline
@item
easy-jekyll
@item
ebdb
@item
ediff
@item
ein (Emacs IPython Notebook)
@item
eglot
@item
el-search
@item
eldoc-box
@item
elfeed
@item
elfeed-score
@item
elpher
@item
embark
@item
ement
@item
emms
@item
enh-ruby-mode (enhanced-ruby-mode)
@item
epa
@item
equake
@item
erc
@item
eros
@item
ert
@item
eshell
@item
eshell-fringe-status
@item
eshell-git-prompt
@item
eshell-prompt-extras (epe)
@item
eshell-syntax-highlighting
@item
evil* (evil-mode)
@item
evil-goggles
@item
evil-snipe
@item
evil-visual-mark-mode
@item
eww
@item
exwm
@item
eyebrowse
@item
fancy-dabbrev
@item
flycheck
@item
flycheck-color-mode-line
@item
flycheck-indicator
@item
flycheck-posframe
@item
flymake
@item
flyspell
@item
flx
@item
freeze-it
@item
focus
@item
fold-this
@item
font-lock (generic syntax highlighting)
@item
forge
@item
fountain (fountain-mode)
@item
geiser
@item
git-commit
@item
git-gutter (and variants)
@item
git-rebase
@item
git-timemachine
@item
gnus
@item
gotest
@item
golden-ratio-scroll-screen
@item
helm*
@item
helm-ls-git
@item
helm-switch-shell
@item
helm-xref
@item
helpful
@item
highlight-indentation
@item
highlight-numbers
@item
highlight-parentheses (@ref{Note on highlight-parenthesesel, , Note on highlight-parentheses.el})
@item
highlight-thing
@item
hl-defined
@item
hl-fill-column
@item
hl-line-mode
@item
hl-todo
@item
hydra
@item
ibuffer
@item
icomplete
@item
icomplete-vertical
@item
ido-mode
@item
iedit
@item
iflipb
@item
image-dired
@item
imenu-list
@item
indium
@item
info
@item
info+ (info-plus)
@item
info-colors
@item
interaction-log
@item
ioccur
@item
isearch, occur, etc.
@item
ivy*
@item
ivy-posframe
@item
jira (org-jira)
@item
journalctl-mode
@item
js2-mode
@item
julia
@item
jupyter
@item
kaocha-runner
@item
keycast
@item
ledger-mode
@item
leerzeichen
@item
line numbers (@code{display-line-numbers-mode} and global variant)
@item
lsp-mode
@item
lsp-ui
@item
macrostep
@item
magit
@item
magit-imerge
@item
make-mode
@item
man
@item
marginalia
@item
markdown-mode
@item
markup-faces (@code{adoc-mode})
@item
mentor
@item
messages
@item
mini-modeline
@item
minimap
@item
mmm-mode
@item
mode-line
@item
mood-line
@item
moody
@item
mpdel
@item
mu4e
@item
multiple-cursors
@item
nano-modeline
@item
neotree
@item
notmuch
@item
num3-mode
@item
nxml-mode
@item
olivetti
@item
orderless
@item
org*
@item
org-journal
@item
org-noter
@item
org-pomodoro
@item
org-recur
@item
org-roam
@item
org-superstar
@item
org-table-sticky-header
@item
org-tree-slide
@item
origami
@item
outline-mode
@item
outline-minor-faces
@item
package (what you get with @kbd{M-x list-packages})
@item
page-break-lines
@item
pandoc-mode
@item
paren-face
@item
pass
@item
pdf-tools
@item
persp-mode
@item
perspective
@item
phi-grep
@item
pomidor
@item
popup
@item
powerline
@item
powerline-evil
@item
prism (@ref{Note for prism, , Note for prism.el})
@item
prescient
@item
proced
@item
prodigy
@item
pulse
@item
pyim
@item
quick-peek
@item
racket-mode
@item
rainbow-blocks
@item
rainbow-delimiters
@item
rcirc
@item
recursion-indicator
@item
regexp-builder (also known as @code{re-builder})
@item
rg (rg.el)
@item
ripgrep
@item
rmail
@item
ruler-mode
@item
selectrum
@item
selectrum-prescient
@item
semantic
@item
sesman
@item
shell-script-mode
@item
shortdoc
@item
show-paren-mode
@item
shr
@item
side-notes
@item
sieve-mode
@item
skewer-mode
@item
slime (slbd)
@item
sly
@item
smart-mode-line
@item
smartparens
@item
smerge
@item
spaceline
@item
speedbar
@item
spell-fu
@item
stripes
@item
suggest
@item
switch-window
@item
swiper
@item
sx
@item
symbol-overlay
@item
syslog-mode
@item
tab-bar-groups
@item
tab-bar-mode
@item
tab-line-mode
@item
table (built-in @file{table.el})
@item
telega
@item
telephone-line
@item
terraform-mode
@item
term
@item
textsec
@item
tomatinho
@item
transient (pop-up windows such as Magit's)
@item
trashed
@item
tree-sitter
@item
treemacs
@item
tty-menu
@item
tuareg
@item
typescript
@item
undo-tree
@item
vc (@file{vc-dir.el}, @file{vc-hooks.el})
@item
vertico
@item
vertico-quick
@item
vimish-fold
@item
visible-mark
@item
visual-regexp
@item
vterm
@item
vundo
@item
wcheck-mode
@item
web-mode
@item
wgrep
@item
which-function-mode
@item
which-key
@item
whitespace-mode
@item
window-divider-mode
@item
winum
@item
writegood-mode
@item
woman
@item
xah-elisp-mode
@item
xref
@item
xterm-color (and ansi-colors)
@item
yaml-mode
@item
yasnippet
@item
ztree
@end itemize

Plus many other miscellaneous faces that are provided by Emacs.

@node Indirectly covered packages
@section Indirectly covered packages

@cindex Implicitly supported packages

These do not require any extra styles because they are configured to
inherit from some basic faces or their dependencies which are directly
supported by the themes.

@itemize
@item
ag
@item
apt-sources-list
@item
buffer-expose
@item
bufler
@item
counsel-notmuch
@item
counsel-org-capture-string
@item
dashboard (emacs-dashboard)
@item
define-word
@item
disk-usage
@item
dtache
@item
dynamic-ruler
@item
easy-kill
@item
edit-indirect
@item
egerrit
@item
elfeed-summary
@item
evil-owl
@item
flyspell-correct
@item
fortran-mode
@item
git-walktree
@item
goggles
@item
highlight-defined
@item
highlight-escape-sequences (@code{hes-mode})
@item
i3wm-config-mode
@item
minibuffer-line
@item
no-emoji
@item
org-remark
@item
parrot
@item
perl-mode
@item
php-mode
@item
rjsx-mode
@item
side-hustle
@item
spell-fu
@item
swift-mode
@item
tab-bar-echo-area
@item
tide
@item
undo-hl
@item
vdiff
@item
vertico-indexed
@item
vertico-mouse
@end itemize

@node Notes on individual packages
@chapter Notes on individual packages

This section covers information that may be of interest to users of
individual packages.

@menu
* Note on calendar.el weekday and weekend colors: Note on calendarel weekday and weekend colors. 
* Note on git-gutter in Doom Emacs::
* Note on php-mode multiline comments::
* Note on underlines in compilation buffers::
* Note on inline Latex in Org buffers::
* Note on dimmer.el: Note on dimmerel. 
* Note on display-fill-column-indicator-mode::
* Note on highlight-parentheses.el: Note on highlight-parenthesesel. 
* Note on mmm-mode.el background colors: Note on mmm-modeel background colors. 
* Note for prism::
* Note for god-mode::
* Note on company-mode overlay pop-up::
* Note on ERC escaped color sequences::
* Note on powerline or spaceline::
* Note on SHR colors::
* Note on SHR fonts::
* Note on Ement colors and fonts::
* Note on Helm grep::
* Note on pdf-tools link hints::
* Note on the Notmuch logo::
* Note on goto-address-mode faces::
@end menu

@node Note on calendarel weekday and weekend colors
@section Note on calendar.el weekday and weekend colors

By default, the @kbd{M-x calendar} interface differentiates weekdays from
weekends by applying a gray color to the former and a faint red to the
latter.  The idea for this approach is that the weekend should serve as
a subtle warning that no work is supposed to be done on that day, per
the design of traditional calendars.

Users who prefer all days to look the same can configure the variable
@code{calendar-weekend-days} to either use gray of weekdays or the faint red of
weekends uniformly.

@lisp
;; All are treated like weekdays (gray color)
(setq calendar-weekend-days nil)

;; All are treated like weekends (red-faint color)
(setq calendar-weekend-days (number-sequence 0 6))

;; The default marks the Saturday and Sunday as the weekend
(setq calendar-weekend-days '(0 6))
@end lisp

For changes to take effect, the Calendar buffer needs to be generated
anew.

@node Note on git-gutter in Doom Emacs
@section Note on git-gutter in Doom Emacs

The @samp{git-gutter} and @samp{git-gutter-fr} packages default to drawing bitmaps
for the indicators they display (e.g. bitmap of a plus sign for added
lines).  In Doom Emacs, these bitmaps are replaced with contiguous lines
which may look nicer, but require a change to the foreground of the
relevant faces to yield the desired color combinations.

Since this is Doom-specific, we urge users to apply changes in their
local setup.  Below is some sample code, based on what we cover at
length elsewhere in this manual:

@ref{Advanced customization}.

@ref{Face specs at scale using the themes' palette}.

@lisp
(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     ;; Replace green with blue if you use `modus-themes-deuteranopia'.
     `(git-gutter-fr:added ((,class :foreground ,green-fringe-bg)))
     `(git-gutter-fr:deleted ((,class :foreground ,red-fringe-bg)))
     `(git-gutter-fr:modified ((,class :foreground ,yellow-fringe-bg))))))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-custom-faces)
@end lisp

As always, re-load the theme for changes to take effect.

If the above does not work, try this instead:

@lisp
(after! modus-themes
  (modus-themes-with-colors
    (custom-set-faces
     ;; Replace green with blue if you use `modus-themes-deuteranopia'.
     `(git-gutter-fr:added ((,class :foreground ,green-fringe-bg)))
     `(git-gutter-fr:deleted ((,class :foreground ,red-fringe-bg)))
     `(git-gutter-fr:modified ((,class :foreground ,yellow-fringe-bg))))))
@end lisp

Replace @code{green-fringe-bg} with @code{blue-fringe-bg} if you want to optimize
for red-green color deficiency.

@ref{Deuteranopia style, , Option for red-green color deficiency or deuteranopia}.

@node Note on php-mode multiline comments
@section Note on php-mode multiline comments

Depending on your build of Emacs and/or the environment it runs in,
multiline comments in PHP with the @samp{php-mode} package use the
@code{font-lock-doc-face} instead of @code{font-lock-comment-face}.

This seems to make all comments use the appropriate face:

@lisp
(defun my-multine-comments ()
  (setq-local c-doc-face-name 'font-lock-comment-face))

(add-hook 'php-mode-hook #'my-multine-comments)
@end lisp

As always, re-load the theme for changes to take effect.

@node Note on underlines in compilation buffers
@section Note on underlines in compilation buffers

Various buffers that produce compilation results or run tests on code
apply an underline to the file names they reference or to relevant
messages.  Users may consider this unnecessary or excessive.

To outright disable the effect, use this (buffers need to be generated
anew):

@lisp
(setq compilation-message-face nil)
@end lisp

If some element of differentiation is still desired, a good option is to
render the affected text with the @code{italic} face:

@lisp
(setq compilation-message-face 'italic)
@end lisp

@ref{Configure bold and italic faces}.

@node Note on inline Latex in Org buffers
@section Note on inline Latex in Org buffers

Org can work with inline latex and related syntax.  To actually fontify
those constructs, set the variable @code{org-highlight-latex-and-related} to
the desired list of values (per its doc string).  For example:

@lisp
(setq org-highlight-latex-and-related '(latex script))
@end lisp

Remember to use @kbd{M-x org-mode-restart} for changes to take effect.

@node Note on dimmerel
@section Note on dimmer.el

The @file{dimmer.el} library by Neil Okamoto can be configured to
automatically dim the colors of inactive Emacs windows.  To guarantee
consistent results with the Modus themes, we suggest some tweaks to the
default styles, such as in this minimal setup:

@lisp
(use-package dimmer
  :config
  (setq dimmer-fraction 0.3)
  (setq dimmer-adjustment-mode :foreground)
  (setq dimmer-use-colorspace :rgb)

  (dimmer-mode 1))
@end lisp

Of the above, we strongly recommend the RGB color space because it is
the one that remains faithful to the hueness of the colors used by the
themes.  Whereas the default CIELAB space has a tendency to distort
colors in addition to applying the dim effect, which can be somewhat
disorienting.

The value of the @code{dimmer-fraction} has been selected empirically.  Users
might prefer to tweak it further (increasing it makes the dim effect
more pronounced).

Changing the @code{dimmer-adjustment-mode} is a matter of preference.  Though
because the Modus themes use black and white as their base colors, any
other value for that variable will turn the main background gray.  This
inadvertently leads to the opposite of the intended utility of this
package: it draws too much attention to unfocused windows.

@node Note on display-fill-column-indicator-mode
@section Note on display-fill-column-indicator-mode

The @code{display-fill-column-indicator-mode} uses a typographic character to
draw its line.  This has the downside of creating a dashed line.  The
dashes are further apart depending on how tall the font's glyph height
is and what integer the @code{line-spacing} is set to.

At the theme level we eliminate this effect by making the character one
pixel tall: the line is contiguous.  Users who prefer the dashed line
are advised to change the @code{fill-column-indicator} face, as explained
elsewhere in this document.  For example:

@lisp
(modus-themes-with-colors
  (custom-set-faces
   `(fill-column-indicator ((,class :foreground ,bg-active)))))
@end lisp

@ref{Face specs at scale using the themes' palette}.

To make the line thicker, set the height to be equal to the base font
size instead of the one pixel we use.  This is done by specifying a rate
instead of an absolute number, as in @samp{:height 1.0} versus @samp{:height 1}.
For example:

@lisp
(modus-themes-with-colors
  (custom-set-faces
   `(fill-column-indicator ((,class :height 1.0 :background ,bg-inactive :foreground ,bg-inactive)))))
@end lisp

@node Note on highlight-parenthesesel
@section Note on highlight-parentheses.el

The @samp{highlight-parentheses} package provides contextual coloration of
surrounding parentheses, highlighting only those which are around the
point.  The package expects users to customize the applicable colors on
their own by configuring certain variables.

To make the Modus themes work as expected with this, we need to use some
of the techniques that are discussed at length in the various
``Do-It-Yourself'' (DIY) sections, which provide insight into the more
advanced customization options of the themes.

@ref{Advanced customization}.

In the following example, we are assuming that the user wants to (i)
reuse color variables provided by the themes, (ii) be able to retain
their tweaks while switching between @code{modus-operandi} and @code{modus-vivendi},
and (iii) have the option to highlight either the foreground of the
parentheses or the background as well.

We start by defining our own variable, which will serve as a toggle
between foreground and background coloration styles:

@lisp
(defvar my-highlight-parentheses-use-background t
  "Prefer `highlight-parentheses-background-colors'.")
@end lisp

Then we can update our preference with this:

@lisp
;; Set to nil to disable backgrounds.
(setq my-highlight-parentheses-use-background nil)
@end lisp

To reuse colors from the themes, we must wrap our code in the
@code{modus-themes-with-colors} macro.  Our implementation must interface with
the variables @code{highlight-parentheses-background-colors} and/or
@code{highlight-parentheses-colors}.

So we can have something like this (the doc string of
@code{modus-themes-with-colors} explains where the names of the colors can be
found):

@lisp
(modus-themes-with-colors
    ;; Our preference for setting either background or foreground
    ;; styles, depending on `my-highlight-parentheses-use-background'.
    (if my-highlight-parentheses-use-background

        ;; Here we set color combinations that involve both a background
        ;; and a foreground value.
        (setq highlight-parentheses-background-colors (list cyan-refine-bg
                                                            magenta-refine-bg
                                                            green-refine-bg
                                                            yellow-refine-bg)
              highlight-parentheses-colors (list cyan-refine-fg
                                                 magenta-refine-fg
                                                 green-refine-fg
                                                 yellow-refine-fg))

      ;; And here we pass only foreground colors while disabling any
      ;; backgrounds.
      (setq highlight-parentheses-colors (list green-intense
                                               magenta-intense
                                               blue-intense
                                               red-intense)
            highlight-parentheses-background-colors nil)))

;; Include this if you also want to make the parentheses bold:
(set-face-attribute 'highlight-parentheses-highlight nil :inherit 'bold)

;; Our changes must be evaluated before enabling the relevant mode, so
;; this comes last.
(global-highlight-parentheses-mode 1)
@end lisp

For our changes to persist while switching between the Modus themes, we
need to include them in a function which can then get passed to
@code{modus-themes-after-load-theme-hook}.  This is the complete
implementation:

@lisp
;; Configurations for `highlight-parentheses':
(require 'highlight-parentheses)

(defvar my-highlight-parentheses-use-background t
  "Prefer `highlight-parentheses-background-colors'.")

(setq my-highlight-parentheses-use-background nil) ; Set to nil to disable backgrounds

(defun my-modus-themes-highlight-parentheses ()
  (modus-themes-with-colors
    ;; Our preference for setting either background or foreground
    ;; styles, depending on `my-highlight-parentheses-use-background'.
    (if my-highlight-parentheses-use-background

        ;; Here we set color combinations that involve both a background
        ;; and a foreground value.
        (setq highlight-parentheses-background-colors (list cyan-refine-bg
                                                            magenta-refine-bg
                                                            green-refine-bg
                                                            yellow-refine-bg)
              highlight-parentheses-colors (list cyan-refine-fg
                                                 magenta-refine-fg
                                                 green-refine-fg
                                                 yellow-refine-fg))

      ;; And here we pass only foreground colors while disabling any
      ;; backgrounds.
      (setq highlight-parentheses-colors (list green-intense
                                               magenta-intense
                                               blue-intense
                                               red-intense)
            highlight-parentheses-background-colors nil)))

  ;; Include this if you also want to make the parentheses bold:
  (set-face-attribute 'highlight-parentheses-highlight nil :inherit 'bold)

  ;; Our changes must be evaluated before enabling the relevant mode, so
  ;; this comes last.
  (global-highlight-parentheses-mode 1))

(add-hook 'modus-themes-after-load-theme-hook #'my-modus-themes-highlight-parentheses)
@end lisp

As always, re-load the theme for changes to take effect.

@node Note on mmm-modeel background colors
@section Note on mmm-mode.el background colors

The faces used by @file{mmm-mode.el} are expected to have a colorful
background, while they should not touch any foreground value.  The idea
is that they must not interfere with existing fontification.  Those
background colors need to be distinct from each other, such as an
unambiguous red juxtaposed with a clear blue.

While this design may be internally consistent with the raison d'être of
that library, it inevitably produces inaccessible color combinations.

There are two competing goals at play:

@enumerate
@item
Legibility of the text, understood as the contrast ratio between the
background and the foreground.

@item
Semantic precision of each face which entails faithfulness to
color-coding of the underlying background.
@end enumerate

As the Modus themes are designed with the express purpose of conforming
with the first point, we have to forgo the apparent color-coding of the
background elements.  Instead we use subtle colors that do not undermine
the legibility of the affected text while they still offer a sense of
added context.

Users who might prefer to fall below the minimum 7:1 contrast ratio in
relative luminance (the accessibility target we conform with), can opt
to configure the relevant faces on their own.

@ref{Face specs at scale using the themes' palette}.

This example uses more vivid background colors, though it comes at the
very high cost of degraded legibility.

@lisp
(modus-themes-with-colors
  (custom-set-faces
   `(mmm-cleanup-submode-face ((,class :background ,yellow-refine-bg)))
   `(mmm-code-submode-face ((,class :background ,bg-active)))
   `(mmm-comment-submode-face ((,class :background ,blue-refine-bg)))
   `(mmm-declaration-submode-face ((,class :background ,cyan-refine-bg)))
   `(mmm-default-submode-face ((,class :background ,bg-alt)))
   `(mmm-init-submode-face ((,class :background ,magenta-refine-bg)))
   `(mmm-output-submode-face ((,class :background ,red-refine-bg)))
   `(mmm-special-submode-face ((,class :background ,green-refine-bg)))))
@end lisp

@node Note for prism
@section Note on prism.el

This package by Adam Porter, aka ``alphapapa'' or ``github-alphapapa'',
implements an alternative to the typical coloration of code.  Instead of
highlighting the syntactic constructs, it applies color to different
levels of depth in the code structure.

As @file{prism.el} offers a broad range of customizations, we cannot
style it directly at the theme level: that would run contrary to the
spirit of the package.  Instead, we may offer preset color schemes.
Those should offer a starting point for users to adapt to their needs.

In the following code snippets, we employ the @code{modus-themes-with-colors}
macro: @ref{Face specs at scale using the themes' palette}.

These are the minimum recommended settings with 16 colors:

@lisp
(setq prism-num-faces 16)

(prism-set-colors
  :desaturations '(0) ; do not change---may lower the contrast ratio
  :lightens '(0)      ; same
  :colors (modus-themes-with-colors
            (list fg-main
                  magenta
                  cyan-alt-other
                  magenta-alt-other
                  blue
                  magenta-alt
                  cyan-alt
                  red-alt-other
                  green
                  fg-main
                  cyan
                  yellow
                  blue-alt
                  red-alt
                  green-alt-other
                  fg-special-warm)))
@end lisp

With 8 colors:

@lisp
(setq prism-num-faces 8)

(prism-set-colors
  :desaturations '(0) ; do not change---may lower the contrast ratio
  :lightens '(0)      ; same
  :colors (modus-themes-with-colors
            (list blue
                  magenta
                  magenta-alt-other
                  cyan-alt-other
                  fg-main
                  blue-alt
                  red-alt-other
                  cyan)))
@end lisp

And this is with 4 colors, which produces results that are the closest
to the themes' default aesthetic:

@lisp
(setq prism-num-faces 4)

(prism-set-colors
  :desaturations '(0) ; do not change---may lower the contrast ratio
  :lightens '(0)      ; same
  :colors (modus-themes-with-colors
            (list blue
                  magenta
                  magenta-alt-other
                  green-alt)))
@end lisp

If you need to apply desaturation and lightening, you can use what the
@file{prism.el} documentation recommends, like this (adapting to the
examples with the 4, 8, 16 colors):

@lisp
(prism-set-colors
  :desaturations (cl-loop for i from 0 below 16 collect (* i 2.5))
  :lightens (cl-loop for i from 0 below 16 collect (* i 2.5))
  :colors (modus-themes-with-colors
            (list fg-main
                  cyan-alt-other
                  magenta-alt-other
                  magenta)))
@end lisp

@node Note for god-mode
@section Note on god-mode.el

The @code{god-mode} library does not provide faces that could be configured by
the Modus themes.  Users who would like to get some visual feedback on
the status of @kbd{M-x god-mode} are instead encouraged by upstream to
set up their own configurations, such as by changing the @code{mode-line} face
(@ref{Advanced customization}).  This is an adaptation of the approach
followed in the upstream README:

@lisp
(defun my-god-mode-update-mode-line ()
  "Make `mode-line' blue if God local mode is active."
  (modus-themes-with-colors
    (if god-local-mode
        (set-face-attribute 'mode-line nil
                            :foreground blue-active
                            :background bg-active-accent
                            :box blue)
      (set-face-attribute 'mode-line nil
                          :foreground fg-active
                          :background bg-active
                          :box fg-alt))))

(add-hook 'post-command-hook 'my-god-mode-update-mode-line)
@end lisp

We employ the @code{modus-themes-with-colors} which provides access to color
variables defined by the active theme.  Its use is covered elsewhere in
this manual (@ref{Face specs at scale using the themes' palette}).  As for the
attributes that can be passed to each face, start by consulting the
documentation string of @code{set-face-attribute}.

@node Note on company-mode overlay pop-up
@section Note on company-mode overlay pop-up

By default, the @code{company-mode} pop-up that lists completion candidates is
drawn using an overlay.  This creates alignment issues every time it is
placed above a piece of text that has a different height than the
default.

The solution recommended by the project's maintainer is to use an
alternative front-end for drawing the pop-up which draws child frames
instead of overlays.@footnote{
@uref{https://github.com/company-mode/company-mode/issues/1010}}@footnote{
@uref{https://github.com/tumashu/company-posframe/}}

@node Note on ERC escaped color sequences
@section Note on ERC escaped color sequences

The built-in IRC client @code{erc} has the ability to colorize any text using
escape sequences that start with @samp{^C} (inserted with @kbd{C-q C-c}) and are
followed by a number for the foreground and background.@footnote{ This page
explains the basics, though it is not specific to Emacs:
@uref{https://www.mirc.com/colors.html}} Possible numbers are 0-15, with the
first entry being the foreground and the second the background,
separated by a comma.  Like this @samp{^C1,6}.  The minimum setup is this:

@lisp
(add-to-list 'erc-modules 'irccontrols)
(setq erc-interpret-controls-p t
      erc-interpret-mirc-color t)
@end lisp

As this allows users the chance to make arbitrary combinations, it is
impossible to guarantee a consistently high contrast ratio.  All we can
we do is provide guidance on the combinations that satisfy the
accessibility standard of the themes:

@table @asis
@item Modus Operandi
Use foreground color 1 for all backgrounds from
2-15.  Like so: @kbd{C-q C-c1} where @samp{N} is the background.

@item Modus Vivendi
Use foreground color 0 for all backgrounds from
2-13.  Use foreground @samp{1} for backgrounds 14, 15.
@end table

Colors 0 and 1 are white and black respectively.  So combine them
together, if you must.

@node Note on powerline or spaceline
@section Note on powerline or spaceline

Both Powerline and Spaceline package users will likely need to use the
command @code{powerline-reset} whenever they make changes to their themes
and/or mode line setup.

@node Note on SHR colors
@section Note on SHR colors

Emacs' HTML rendering library (@file{shr.el}) may need explicit
configuration to respect the theme's colors instead of whatever
specifications the webpage provides.

Consult the doc string of @code{shr-use-colors}.

@node Note on SHR fonts
@section Note on SHR fonts

@cindex Fonts in EWW, Elfeed, Ement, and SHR

By default, packages that build on top of the Simple HTML Remember (@samp{shr})
use proportionately spaced fonts.  This is controlled by the user option
@code{shr-use-fonts}, which is set to non-@code{nil} by default.  To use the standard
font instead, set that variable to nil.

@ref{Font configurations for Org and others}.

Packages affected by this are:

@itemize
@item
elfeed
@item
ement
@item
eww
@end itemize

This is a non-exhaustive list.

@node Note on Ement colors and fonts
@section Note on Ement colors and fonts

The @samp{ement.el} library by Adam Porter (also known as ``alphapapa'') defaults
to a method of colorizing usernames in a rainbow style.  This is
controlled by the user option @code{ement-room-prism} and can be disabled with:

@lisp
(setq ement-room-prism nil)
@end lisp

The contrast ratio of these colors is governed by another user option:
@code{ement-room-prism-minimum-contrast}.  By default, it is set to 6 which is
slightly below our nominal target.  Try this instead:

@lisp
(setq ement-room-prism-minimum-contrast 7)
@end lisp

With regard to fonts, Ement depends on @samp{shr} (@ref{Note on SHR fonts}).

Since we are here, here is an excerpt from Ement's source code:

@lisp
(defcustom ement-room-prism-minimum-contrast 6
  "Attempt to enforce this minimum contrast ratio for user faces.
This should be a reasonable number from, e.g. 0-7 or so."
  ;; Prot would almost approve of this default.  :) I would go all the way
  ;; to 7, but 6 already significantly dilutes the colors in some cases.
  :type 'number)
@end lisp

Yes, I do approve of that default.  Even a 4.5 (the WCAG AA rating)
would be a good baseline for many themes and/or user configurations.
Our target is the highest of the sort, though we do not demand that
everyone conforms with it.

@node Note on Helm grep
@section Note on Helm grep

There is one face from the Helm package that is meant to highlight the
matches of a grep or grep-like command (@samp{ag} or @samp{ripgrep}).  It is
@code{helm-grep-match}.  However, this face can only apply when the user does
not pass @samp{--color=always} as a command-line option for their command.

Here is the docstring for that face, which is defined in the
@file{helm-grep.el} library (you can always visit the source code with
@kbd{M-x find-library}).

@quotation
Face used to highlight grep matches.  Have no effect when grep backend
use ``--color=''

@end quotation

The user must either remove @samp{--color} from the flags passed to the grep
function, or explicitly use @samp{--color=never} (or equivalent).  Helm
provides user-facing customization options for controlling the grep
function's parameters, such as @code{helm-grep-default-command} and
@code{helm-grep-git-grep-command}.

When @samp{--color=always} is in effect, the grep output will use red text in
bold letter forms to present the matching part in the list of
candidates.  That style still meets the contrast ratio target of >= 7:1
(accessibility standard WCAG AAA), because it draws the reference to
ANSI color number 1 (red) from the already-supported array of
@code{ansi-color-names-vector}.

@node Note on pdf-tools link hints
@section Note on pdf-tools link hints

Hints are drawn by @uref{https://imagemagick.org/, ImageMagick}, not Emacs, i.e., ImageMagick doesn't
know about the hint face unless you tell ImageMagick about it.  By
default, only the foreground and background color attributes are
passed.  The below snippet adds to those the various font attributes.  As
it queries various faces, specifically @code{pdf-links-read-link} and the faces
it inherits, it needs to be added to your initialization file after
you've customized any faces.

@lisp
(use-package pdf-links
  :config
  (let ((spec
         (apply #'append
                (mapcar
                 (lambda (name)
                   (list name
                         (face-attribute 'pdf-links-read-link
                                         name nil 'default)))
                 '(:family :width :weight :slant)))))
    (setq pdf-links-read-link-convert-commands
          `("-density"    "96"
            "-family"     ,(plist-get spec :family)
            "-stretch"    ,(let* ((width (plist-get spec :width))
                                  (name (symbol-name width)))
                             (replace-regexp-in-string "-" ""
                                                       (capitalize name)))
            "-weight"     ,(pcase (plist-get spec :weight)
                             ('ultra-light "Thin")
                             ('extra-light "ExtraLight")
                             ('light       "Light")
                             ('semi-bold   "SemiBold")
                             ('bold        "Bold")
                             ('extra-bold  "ExtraBold")
                             ('ultra-bold  "Black")
                             (_weight      "Normal"))
            "-style"      ,(pcase (plist-get spec :slant)
                             ('italic  "Italic")
                             ('oblique "Oblique")
                             (_slant   "Normal"))
            "-pointsize"  "%P"
            "-undercolor" "%f"
            "-fill"       "%b"
            "-draw"       "text %X,%Y '%c'"))))
@end lisp

@node Note on the Notmuch logo
@section Note on the Notmuch logo

By default, the ``hello'' buffer of Notmuch includes a header with the
programs' logo and a couple of buttons.  The logo has the effect of
enlarging the height of the line, which negatively impacts the shape of
those buttons.  Disabling the logo fixes the problem:

@lisp
(setq notmuch-show-logo nil)
@end lisp

@node Note on goto-address-mode faces
@section Note on goto-address-mode faces

The built-in @code{goto-address-mode} uses heuristics to identify URLs and
email addresses in the current buffer.  It then applies a face to them
to change their style.  Some packages, such as @samp{notmuch}, use this
minor-mode automatically.

The faces are not declared with @code{defface}, meaning that it is better
that the theme does not modify them.  The user is thus encouraged to
consider including (or equivalent) this in their setup:

@lisp
(setq goto-address-url-face 'link
      goto-address-url-mouse-face 'highlight
      goto-address-mail-face 'link
      goto-address-mail-mouse-face 'highlight)
@end lisp

My personal preference is to set @code{goto-address-mail-face} to nil, as
it otherwise adds too much visual noise to the buffer (email addresses
stand out more, due to the use of the uncommon @samp{@@} character but also
because they are often enclosed in angled brackets).

@node Frequently Asked Questions
@chapter Frequently Asked Questions

@cindex Frequently Asked Questions

In this section we provide answers related to some aspects of the Modus
themes' design and application.

@menu
* Is the contrast ratio about adjacent colors?::
* What does it mean to avoid exaggerations?::
* Why are colors mostly variants of blue, magenta, cyan?: Why are colors mostly variants of blue magenta cyan?. 
* What is the best setup for legibility?::
* Are these color schemes?::
* Port the Modus themes to other platforms?::
@end menu

@node Is the contrast ratio about adjacent colors?
@section Is the contrast ratio about adjacent colors?

@cindex Contrast between adjacent colors

The minimum contrast ratio in relative luminance that the themes conform
with always refers to any given combination of background and foreground
colors.  If we have some blue colored text next to a magenta one, both
against a white background, we do not mean to imply that blue:magenta is
7:1 in terms of relative luminance.  Rather, we state that blue:white
and magenta:white each are 7:1 or higher.

The point of reference is always the background.  Because colors have
about the same minimum distance in luminance from their backdrop, they
necessarily are fairly close to each other in this measure.  A possible
blue:magenta combination would naturally be around 1:1 in contrast of
the sort here considered.

To differentiate between sequential colors, we rely on hueness by
mapping contrasting hues to adjacent constructs, while avoiding
exaggerations.  A blue next to a magenta can be told apart regardless of
their respective contrast ratio against their common background.
Exceptions would be tiny characters in arguably not so realistic cases,
such as two dots drawn side-by-side which for some reason would need to
be colored differently.  They would still be legible though, which is
the primary objective of the Modus themes.

@node What does it mean to avoid exaggerations?
@section What does it mean to avoid exaggerations?

@cindex Avoiding exaggerations in design

The Modus themes are designed with restraint, so that their default
looks do not overdo it with the application of color.

@ref{Customization Options}.

This is the non-quantifiable aspect of the themes' design: the artistic
part, if you will.  There are a lot of cases where color can be used
inconsiderately, without accounting for layout, typographic, or other
properties of the presentation.  For example, two headings with distinct
markers, such as leading asterisks in Org buffers, do not have to have
highly contrasting hues between them in order to be told apart: the
added element of contrast in hueness does not contribute significantly
more to the distinction between the headings than colors whose hues are
relatively closer to each other in the color space.

Exaggerations can be hard to anticipate or identify.  Multiple shades of
blue and magenta in the same context may not seem optimal: one might
think that it would be better to use highly contrasting hues to ensure
that all colors stand out, such as by placing blue next to yellow, next
to magenta, and green.  That would, however, be a case of design for its
own sake; a case where color is being applied without consideration of
its end results in the given context.  Too many contrasting hues in
close proximity force an erratic rate to how the eye jumps from one
piece of text to the next.  Whereas multiple shades of, say, blue and
magenta can suffice to tell things apart and avoid excess coloration: a
harmonious rhythm.

@node Why are colors mostly variants of blue magenta cyan?
@section Why are colors mostly variants of blue, magenta, cyan?

@cindex Innate color qualities of the palette

Due to the innate properties of color, some options are better than
others for the accessibility purposes of the themes, the stylistic
consistency between @code{modus-operandi} and @code{modus-vivendi}, and the avoidance
of exaggerations in design.

@ref{What does it mean to avoid exaggerations?}

What we describe as color is a function of three distinct channels of
light: red, green, blue.  In hexadecimal RGB notation, a color value is
read as three pairs of red, green, and blue light: @samp{#RRGGBB}.  Of those
three, the most luminant is green, while the least luminant is blue.

The three basic colors represent each of the channels of light.  They
can be intermixed to give us six colors: red and green derive yellow,
green and blue make cyan, red and blue turn into magenta.

We can test the luminance of each of those against white and black to
get a sense of how not all colors are equally good for accessibility
(white is @samp{#ffffff}, which means that all three light channels are fully
luminated, while black is @samp{#000000} meaning that no light is present
(notwithstanding display technology)).

@example
| Name    |         | #ffffff | #000000 |
|---------+---------+---------+---------|
| red     | #ff0000 |    4.00 |    5.25 |
| yellow  | #ffff00 |    1.07 |   19.56 |
| green   | #00ff00 |    1.37 |   15.30 |
| cyan    | #00ffff |    1.25 |   16.75 |
| blue    | #0000ff |    8.59 |    2.44 |
| magenta | #ff00ff |    3.14 |    6.70 |
@end example

@ref{Measure color contrast}.

By reading this table we learn that every color that has a high level of
green light (green, yellow, cyan) is virtually unreadable against a
white background and, conversely, can be easily read against black.

We can then infer that red and blue, in different combinations, with
green acting as calibrator for luminance, will give us fairly moderate
colors that pass the 7:1 target.  Blue with a bit of green produce
appropriate variants of cyan.  Similarly, blue combined with some red
and hints of green give us suitable shades of purple.

Due to the need of maintaining some difference in hueness between
adjacent colors, it is not possible to make red, green, and yellow the
main colors, because blue cannot be used to control their luminance and,
thus the relevant space will shrink considerably.

@ref{Is the contrast ratio about adjacent colors?}

This phenomenon is best illustrated by the following table that measures
the relative luminance of shades of red, yellow, magenta against white:

@example
|         | #ffffff |
|---------+---------|
| #990000 |    8.92 |
| #995500 |    5.75 |
| #990099 |    7.46 |
@end example

We notice that equal values of red and blue light in @samp{#990099} (magenta
shade) do not lead to a considerable change in luminance compared with
@samp{#990000} (red variant).  Whereas less amount of green light in @samp{#995500}
leads to a major drop in luminance relative to white.  It follows that
using the green channel of light to calibrate the luminance of colors is
more effective than trying to do the same with either red or blue (the
latter is the least effective in that regard).

When we need to work with several colors, it is always better to have
sufficient maneuvering space, especially since we cannot pick arbitrary
colors but only those that satisfy the accessibility objectives of the
themes.

As for why we do not mostly use green, yellow, cyan for the dark theme,
it is because those colors are far more luminant than their counterparts
on the other side of the spectrum, so to ensure that they all have about
the same contrast ratios we would have to alter their hueness
considerably.  In short, the effect would not be optimal as it would
lead to exaggerations.  Plus, it would make @code{modus-vivendi} look
completely different than @code{modus-operandi}, to the effect that the two
could not be properly considered part of the same project.

@node What is the best setup for legibility?
@section What is the best setup for legibility?

@cindex General setup for readability

The Modus themes can be conceptually simplified as combinations of color
values that account for relative luminance and inner harmony.  Those
qualities do not guarantee that every end-user will have the same
experience, due to differences between people, but also because of
variances in hardware capabilities and configurations.  For the purposes
of this document, we may only provide suggestions pertaining to the
latter case.

@code{modus-operandi} is best used outdoors or in a room that either gets
direct sunlight or has plenty of light.  Whereas @code{modus-vivendi} works
better when there is not a lot of sunshine or the room has a source of
light that is preferably a faint and/or warm one.  It is possible to use
@code{modus-operandi} at night and @code{modus-vivendi} during the day, though that
will depend on several variables, such as one's overall perception of
color, the paint on the walls and how that contributes to the impression
of lightness in the room, the sense of space within the eye's peripheral
vision, hardware specifications, and environmental factors.

In general, an additional source of light other than that of the monitor
can help reduce eye strain: the eyes are more relaxed when they do not
have to focus on one point to gather light.

The monitor's display settings must be accounted for.  Gamma values, in
particular, need to be calibrated to neither amplify nor distort the
perception of black.  Same principle for sharpness, brightness, and
contrast as determined by the hardware, which all have an effect on how
text is read on the screen.

There are software level methods on offer, such as the XrandR utility
for the X Window System (X.org), which can make gamma corrections for
each of the three channels of light (red, green, blue).  For example:

@example
xrandr --output LVDS1 --brightness 1.0 --gamma 0.76:0.75:0.68
@end example


Typography is another variable.  Some font families are blurry at small
point sizes.  Others may have a regular weight that is lighter (thinner)
than that of their peers which may, under certain circumstances, cause a
halo effect around each glyph.

The gist is that legibility cannot be fully solved at the theme level.
The color combinations may have been optimized for accessibility, though
the remaining contributing factors in each case need to be considered in
full.

@node Are these color schemes?
@section Are these color schemes?

@cindex Themes, not color schemes

No, the Modus themes are not color schemes.

A color scheme is a collection of colors.  A good color scheme is a
combination of colors with an inner logic or abstract structure.

A theme is a set of patterns that are applied across different contexts.
A good theme is one that does so with consistency, though not
uniformity.

In practical terms, a color scheme is what one uses when, for example,
they edit the first sixteen escape sequences of a terminal emulator to
the hues of their preference.  The terminal offers the option to choose,
say, the exact value of what counts as ``red'', but does not provide the
means to control where that is mapped to and whether it should also have
other qualities such as a bold weight for the underlying text or an
added background color.  In contradistinction, Emacs uses constructs
known as ``faces'' which allow the user/developer to specify where a given
color will be used and whether it should be accompanied by other
typographic or stylistic attributes.

By configuring the multitude of faces on offer we thus control both
which colors are applied and how they appear in their context.  When a
package wants to render each instance of ``foo'' with the ``bar'' face, it
is not requesting a specific color, which makes things considerably more
flexible as we can treat ``bar'' in its own right without necessarily
having to use some color value that we hardcoded somewhere.

Which brings us to the distinction between consistency and uniformity
where our goal is always the former: we want things to look similar
across all interfaces, but we must never force a visual identity where
that runs contrary to the functionality of the given interface.  For
instance, all links are underlined by default yet there are cases such
as when viewing listings of emails in Gnus (and Mu4e, Notmuch) where (i)
it is already understood that one must follow the indicator or headline
to view its contents and (ii) underlining everything would make the
interface virtually unusable.

@ref{Link styles, , Option for links}.

Again, one must exercise judgment in order to avoid discrimination,
where ``discrimination'' refers to:

@itemize
@item
The treatment of substantially different magnitudes as if they were of
the same class.
@item
Or the treatment of the same class of magnitudes as if they were of a
different class.
@end itemize

(To treat similar things differently; to treat dissimilar things alike.)

If, in other words, one was to enforce uniformity without accounting for
the particular requirements of each case---the contextual demands for
usability beyond matters of color---they would be making a
not-so-obvious error of treating different cases as if they were the
same.

The Modus themes prioritize ``thematic consistency'' over abstract harmony
or regularity among their applicable colors.  In concrete terms, we do
not claim that, say, our yellows are the best complements for our blues
because we generally avoid using complementary colors side-by-side, so
it is wrong to optimize for a decontextualised blue+yellow combination.
Not to imply that our colors do not work well together because they do,
just to clarify that consistency of context is what themes must strive
for, and that requires widening the scope of the design beyond the
particularities of a color scheme.

Long story short: color schemes and themes have different requirements.
Please do not conflate the two.

@node Port the Modus themes to other platforms?
@section Port the Modus themes to other platforms?

@cindex Porting the themes to other editors

There is no plan to port the themes to other platforms or text editors.
I (Protesilaos) only use GNU Emacs and thus cannot maintain code that
targets software I am either not familiar with or am not using on a
daily basis.

While it is possible to produce a simulacrum based on a given template,
doing so would run contrary to how this project is maintained where
details matter greatly.

Each program has its own requirements so it won't always be
possible---or indeed desirable---to have 1:1 correspondence between what
applies to Emacs and what should be done elsewhere.  No port should ever
strive to be a faithful copy of the Emacs implementation, as no other
program is an Emacs equivalent, but instead try to follow the spirit of
the design.  For example, some of the customization options accept a
list as their value, or an alist, which may not be possible to reproduce
on other platforms.

@ref{Customization Options, , Customization options}.

In other words, if something must be done differently on a certain
editor then that is acceptable so long as (i) the accessibility
standards are not compromised and (ii) the overall character of the
themes remains consistent.

The former criterion should be crystal clear as it pertains to the
scientific foundations of the themes: high legibility and taking care of
the needs of users with red-green color deficiency (deuteranopia) by
avoiding red+green color coding paradigms and/or by providing red+blue
variants.

The latter criterion is the ``je ne sais quoi'' of the artistic aspect of
the themes, which is partially fleshed out in this manual.

@ref{Frequently Asked Questions}.

With regard to the artistic aspect (where ``art'' qua skill may amount to
an imprecise science), there is no hard-and-fast rule in effect as it
requires one to exercise discretion and make decisions based on
context-dependent information or constraints.  As is true with most
things in life, when in doubt, do not cling on to the letter of the law
but try to understand its spirit.

For a trivial example: the curly underline that Emacs draws for spelling
errors is thinner than, e.g., what a graphical web browser has, so if I
was to design for an editor than has a thicker curly underline I would
make the applicable colors less intense to counterbalance the
typographic intensity of the added thickness.

With those granted, if anyone is willing to develop a port of the
themes, they are welcome to contact me and I will do my best to help
them in their efforts.

@node Contributing
@chapter Contributing

This section documents the canonical sources of the themes and the ways
in which you can contribute to their ongoing development.

@menu
* Sources of the themes::
* Issues you can help with::
* Patches require copyright assignment to the FSF::
@end menu

@node Sources of the themes
@section Sources of the themes

@cindex Sources of the themes

The @code{modus-operandi} and @code{modus-vivendi} themes are built into Emacs 28.

The source code of the themes is @uref{https://git.sr.ht/~protesilaos/modus-themes, available on SourceHut}.  Or check the
@uref{https://gitlab.com/protesilaos/modus-themes/, GitLab mirror (former main source)} and the @uref{https://github.com/protesilaos/modus-themes/, GitHub mirror}.

An HTML version of this manual is provided as an extension of the
@uref{https://protesilaos.com/emacs/modus-themes/, author's personal website} (does not rely on any non-free code).

@node Issues you can help with
@section Issues you can help with

@cindex Contributing

@findex modus-themes-report-bug
A few tasks you can help with by sending an email to the general
@uref{https://lists.sr.ht/~protesilaos/modus-themes, modus-themes public mailing list} (or use the command
@code{modus-themes-report-bug}).

@itemize
@item
Suggest refinements to packages that are covered.
@item
Report packages not covered thus far.
@item
Report bugs, inconsistencies, shortcomings.
@item
Help expand the documentation of covered-but-not-styled packages.
@item
Suggest refinements to the color palette.
@item
Help expand this document or any other piece of documentation.
@item
Send patches for code refinements (if you need, ask me for help with
Git---we all start out as beginners).
@end itemize

@ref{Patches require copyright assignment to the FSF}.

It is preferable that your feedback includes some screenshots, GIFs, or
short videos, as well as further instructions to reproduce a given
setup.  Though this is not a requirement.

@findex modus-themes-version
Also consider mentioning the version of the themes you are using, such
as by invoking the command @code{modus-themes-version}.

Whatever you do, bear in mind the overarching objective of the Modus
themes: to keep a contrast ratio that is greater or equal to 7:1 between
background and foreground colors.  If a compromise is ever necessary
between aesthetics and accessibility, it shall always be made in the
interest of the latter.

@node Patches require copyright assignment to the FSF
@section Patches require copyright assignment to the FSF

Code contributions are most welcome.  For any major edit (more than 15
lines, or so, in aggregate per person), you need to make a copyright
assignment to the Free Software Foundation.  This is necessary because
the themes are part of the upstream Emacs distribution: the FSF must at
all times be in a position to enforce the GNU General Public License.

Copyright assignment is a simple process.  Check the request form below
(please adapt it accordingly).  You must write an email to the address
mentioned in the form and then wait for the FSF to send you a legal
agreement.  Sign the document and file it back to them.  This could all
happen via email and take about a week.  You are encouraged to go
through this process.  You only need to do it once.  It will allow you
to make contributions to Emacs in general.

@example
Please email the following information to assign@@gnu.org, and we
will send you the assignment form for your past and future changes.

Please use your full legal name (in ASCII characters) as the subject
line of the message.

REQUEST: SEND FORM FOR PAST AND FUTURE CHANGES

[What is the name of the program or package you're contributing to?]

GNU Emacs

[Did you copy any files or text written by someone else in these changes?
Even if that material is free software, we need to know about it.]

Copied a few snippets from the same files I edited.  Their author,
Protesilaos Stavrou, has already assigned copyright to the Free Software
Foundation.

[Do you have an employer who might have a basis to claim to own
your changes?  Do you attend a school which might make such a claim?]


[For the copyright registration, what country are you a citizen of?]


[What year were you born?]


[Please write your email address here.]


[Please write your postal address here.]





[Which files have you changed so far, and which new files have you written
so far?]

@end example

@node Acknowledgements
@chapter Acknowledgements

@cindex Contributors

The Modus themes are a collective effort.  Every bit of work matters.

@table @asis
@item Author/maintainer
Protesilaos Stavrou.

@item Contributions to code or documentation
Alex Griffin, Anders
Johansson, Antonio Ruiz, Basil L@.@:  Contovounesios, Björn
Lindström, Carlo Zancanaro, Christian Tietze, Daniel Mendler, Eli
Zaretskii, Fritz Grabo, Illia Ostapyshyn, Kévin Le Gouguec, Koen van
Greevenbroek, Kostadin Ninev, Madhavan Krishnan, Manuel Giraud,
Markus Beppler, Matthew Stevenson, Mauro Aranda, Nicolas De
Jaeghere, Paul David, Philip Kaludercic, Pierre Téchoueyres, Rudolf
Adamkovič, Stephen Gildea, Shreyas Ragavan, Stefan Kangas, Utkarsh
Singh, Vincent Murphy, Xinglu Chen, Yuanchen Xie, okamsn.

@item Ideas and user feedback
Aaron Jensen, Adam Porter, Adam Spiers,
Adrian Manea, Alex Griffin, Alex Koen, Alex Peitsinis, Alexey
Shmalko, Alok Singh, Anders Johansson, André Alexandre Gomes, Andrew
Tropin, Antonio Hernández Blas, Arif Rezai, Augusto Stoffel, Basil
L@.@:  Contovounesios, Burgess Chang, Christian Tietze,
Christopher Dimech, Christopher League, Damien Cassou, Daniel
Mendler, Dario Gjorgjevski, David Edmondson, Davor Rotim, Divan
Santana, Eliraz Kedmi, Emanuele Michele Alberto Monterosso, Farasha
Euker, Feng Shu, Gautier Ponsinet, Gerry Agbobada, Gianluca Recchia,
Gonçalo Marrafa, Guilherme Semente, Gustavo Barros, Hörmetjan
Yiltiz, Ilja Kocken, Iris Garcia, Ivan Popovych, Jeremy Friesen,
Jerry Zhang, Johannes Grødem, John Haman, Jonas Collberg, Jorge
Morais, Joshua O'Connor, Julio C@. Villasante, Kenta Usami, Kevin
Fleming, Kévin Le Gouguec, Kevin Kainan Li, Kostadin Ninev, Len
Trigg, Lennart C@. Karssen, Luis Miguel Castañeda, Magne Hov, Manuel
Uberti, Mark Bestley, Mark Burton, Mark Simpson, Markus Beppler,
Matt Armstrong, Matthias Fuchs, Mauro Aranda, Maxime Tréca, Michael
Goldenberg, Morgan Smith, Morgan Willcock, Murilo Pereira, Nicky van
Foreest, Nicolas De Jaeghere, Pablo Stafforini, Paul Poloskov,
Pengji Zhang, Pete Kazmier, Peter Wu, Philip Kaludercic, Pierre
Téchoueyres, Przemysław Kryger, Robert Hepple, Roman Rudakov, Ryan
Phillips, Rytis Paškauskas, Rudolf Adamkovič, Sam Kleinman, Samuel
Culpepper, Saša Janiška, Shreyas Ragavan, Simon Pugnet, Tassilo
Horn, Thibaut Verron, Thomas Heartman, Togan Muftuoglu, Tony Zorman,
Trey Merkley, Tomasz Hołubowicz, Toon Claes, Uri Sharf, Utkarsh
Singh, Vincent Foley.  As well as users: Ben, CsBigDataHub1, Emacs
Contrib, Eugene, Fourchaux, Fredrik, Moesasji, Nick, Summer Emacs,
TheBlob42, Trey, bepolymathe, bit9tream, derek-upham, doolio,
fleimgruber, gitrj95, iSeeU, jixiuf, okamsn, pRot0ta1p.

@item Packaging
Basil L@.@:  Contovounesios, Eli Zaretskii,
Glenn Morris, Mauro Aranda, Richard Stallman, Stefan Kangas (core
Emacs), Stefan Monnier (GNU Elpa), André Alexandre Gomes, Andrew
Tropin, Dimakakos Dimos, Morgan Smith, Nicolas Goaziou (Guix), Dhavan
Vaidya (Debian).

@item Inspiration for certain features
Bozhidar Batsov (zenburn-theme),
Fabrice Niessen (leuven-theme).
@end table

Special thanks (from A-Z) to Daniel Mendler, Gustavo Barros, Manuel
Uberti, Nicolas De Jaeghere, and Omar Antolín Camarena for their long
time contributions and insightful commentary on key aspects of the
themes' design and/or aspects of their functionality.

All errors are my own.

@node Other notes about the project
@chapter Other notes about the project

@cindex Development notes

If you are curious about the principles that govern the development of
this project read the essay @uref{https://protesilaos.com/codelog/2020-03-17-design-modus-themes-emacs/, On the design of the Modus themes}
(2020-03-17).

Here are some more publications for those interested in the kind of work
that goes into this project (sometimes the commits also include details
of this sort):

@itemize
@item
@uref{https://protesilaos.com/codelog/2020-05-10-modus-operandi-palette-review/, Modus Operandi theme subtle palette review} (2020-05-10)
@item
@uref{https://protesilaos.com/codelog/2020-06-13-modus-vivendi-palette-review/, Modus Vivendi theme subtle palette review} (2020-06-13)
@item
@uref{https://protesilaos.com/codelog/2020-07-04-modus-themes-faint-colours/, Modus themes: new ``faint syntax'' option} (2020-07-04)
@item
@uref{https://protesilaos.com/codelog/2020-07-08-modus-themes-nuanced-colours/, Modus themes: major review of ``nuanced'' colours} (2020-07-08)
@item
@uref{https://protesilaos.com/codelog/2020-09-14-modus-themes-review-blues/, Modus themes: review of blue colours} (2020-09-14)
@item
@uref{https://protesilaos.com/codelog/2020-12-27-modus-themes-review-rainbow-delimiters/, Modus themes: review rainbow-delimiters faces} (2020-12-27)
@item
@uref{https://protesilaos.com/codelog/2021-01-11-modus-themes-review-select-faint-colours/, Modus themes: review of select ``faint'' colours} (2021-01-11)
@item
@uref{https://protesilaos.com/codelog/2021-02-25-modus-themes-diffs-deuteranopia/, The Modus themes now cover deuteranopia in diffs} (2021-02-25)
@item
@uref{https://protesilaos.com/codelog/2021-06-02-modus-themes-org-agenda/, Introducing the variable modus-themes-org-agenda} (2021-06-02)
@item
@uref{https://protesilaos.com/codelog/2022-01-02-review-modus-themes-org-habit-colours/, Modus themes: review of the org-habit graph colours} (2022-01-02)
@item
@uref{https://protesilaos.com/codelog/2022-01-03-modus-themes-port-faq/, Re: VSCode or Vim ports of the Emacs modus-themes?} (2022-01-03)
@item
@uref{https://protesilaos.com/codelog/2022-04-20-modus-themes-case-study-avy/, Modus themes: case study on Avy faces and colour combinations} (2022-04-20)
@item
@uref{https://protesilaos.com/codelog/2022-04-21-modus-themes-colour-theory/, Emacs: colour theory and techniques used in the Modus themes} (2022-04-21)
@end itemize

And here are the canonical sources of this project:

@table @asis
@item Manual
@uref{https://protesilaos.com/emacs/modus-themes}
@item Change Log
@uref{https://protesilaos.com/emacs/modus-themes-changelog}
@item Screenshots
@uref{https://protesilaos.com/emacs/modus-themes-pictures}
@item Git repository
@uref{https://git.sr.ht/~protesilaos/modus-themes}
@item Mailing list
@uref{https://lists.sr.ht/~protesilaos/modus-themes}
@end table

@node GNU Free Documentation License
@appendix GNU Free Documentation License

@include doclicense.texi

@node Indices
@chapter Indices

@menu
* Function index::
* Variable index::
* Concept index::
@end menu

@node Function index
@section Function index

@printindex fn

@node Variable index
@section Variable index

@printindex vr

@node Concept index
@section Concept index

@printindex cp

@bye
