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Modus Themes

Accessible themes for GNU Emacs, conforming with the highest standard for colour contrast between background and foreground values (WCAG AAA)

IMAGES HERE: https://protesilaos.com/emacs/modus-themes-pictures

Official manual

This manual, written by Protesilaos Stavrou, describes the customization options for the Modus themes, and provides every other piece of information pertinent to them.

The documentation furnished herein corresponds to stable version 4.0.0, released on 2023-01-01. 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 4.1.0-dev.

Table of Contents

1. COPYING

Copyright (C) 2020-2023 Free Software Foundation, Inc.

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.”

2. Overview

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

The Modus themes consist of six themes, divided into three subgroups.

Main themes
modus-operandi is the project’s main light theme, while modus-vivendi is its dark counterpart. These two themes are part of the project since its inception. They are designed to cover a broad range of needs and are, in the opinion of the author, the reference for what a highly legible “default” theme should look like.
Tinted themes
modus-operandi-tinted and modus-vivendi-tinted are variants of the two main themes. They slightly tone down the intensity of the background and provide a bit more color variety. modus-operandi-tinted has a set of base tones that are shades of light ochre (earthly colors), while modus-vivendi-tinted gives a night sky impression.
Deuteranopia themes
modus-operandi-deuteranopia and its companion modus-vivendi-deuteranopia are optimized for users with red-green color deficiency. This means that they do not use red and green hues for color-coding purposes, such as for diff removed and added lines. Instead, they implement colors that are discernible by users with deueteranopia or deuteranomaly (mostly yellow and blue hues).

To ensure that users have a consistently accessible experience, the themes strive to achieve as close to full face coverage as possible, while still targeting a curated list of well-maintained packages (Face coverage).

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.

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

2.1. How do the themes look like

Check the web page with the screen shots. Note that the themes are highly customizable (Customization options).

2.2. Learn about the latest changes

Please refer to the web page with the change log. It is comprehensive and covers everything that goes into every tagged release of the themes.

3. 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.

Emacs 28 ships with modus-themes version 1.6.0. Emacs 29 includes version 3.0.0. Emacs 30 provides a newer, refactored version that thoroughly refashions how the themes are implemented and customized. Such major versions are not backward-compatible due to the limited resources at the maintainer’s disposal to support multiple versions of Emacs and of the themes across the years.

3.1. Install manually from source

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

  1. Get the source and store it in the desired path by running the following in the command line shell:
$ git clone https://gitlab.com/protesilaos/modus-themes.git ~/.emacs.d/modus-themes
  1. Add that path to your known Elisp libraries’ list, by placing this snippet of Emacs Lisp in your init file (e.g. init.el):
(add-to-list 'load-path "~/.emacs.d/modus-themes")

The themes are now ready to be used: Enable and load.

3.2. Install from the archives

The 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 M-x package-refresh-contents. Then all you need to do is type M-x package-install and specify the modus-themes.

Once installed, the themes are ready to be used: Enable and load.

3.3. 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.

3.3.1. Debian 11 Bullseye

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

sudo apt install elpa-modus-themes

They are now ready to be used: Enable and load.

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

3.3.2. GNU Guix

Users of Guix can get the themes with this command:

guix package -i emacs-modus-themes

They are now ready to be used: Enable and load.

3.4. 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 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:

  1. Delete the modus-themes package.
  2. Close the current Emacs session.
  3. Install the modus-themes again.

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.

Issues you can help with.

4. Enable and load

NOTE that Emacs can load multiple themes, which typically produces undesirable results and undoes the work of the designer. Use the disable-theme command if you are trying other themes beside the Modus collection (Option for disabling other themes while loading Modus).

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

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

Remember that the Modus themes are six themes (Overview). Adapt the above snippet accordingly.

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 one of the themes:

(require 'modus-themes)

One can activate a theme with something like the following expression, replacing modus-operandi with their preferred Modus theme:

(load-theme 'modus-operandi :no-confirm)

Changes to the available customization options must always be evaluated before loading a theme (Customization Options). Reload a theme for new changes to take effect.

This is how a basic setup could look like (The require-theme for built-in Emacs themes):

;;; For the built-in themes which cannot use `require'.
(require-theme 'modus-themes)

;; Add all your customizations prior to loading the themes.
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil)

;; Load the theme of your choice.
(load-theme 'modus-operandi)

;; Optionally define a key to switch between Modus themes.  Also check
;; the user option `modus-themes-to-toggle'.
(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)

;; Load the theme of your choice.
(load-theme 'modus-operandi :no-confirm)

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

Sample configuration with and without use-package.

4.1. The require-theme for built-in Emacs themes

The version of the Modus themes that is included in Emacs CANNOT use the standard require. This is because the built-in themes are not included in the load-path (not my decision). The require-theme function must be used in this case as a replacement. For example:

(require-theme 'modus-themes)

;; All customizations here
(setq modus-themes-bold-constructs t
      modus-themes-italic-constructs t)

;; Maybe define some palette overrides, such as by using our presets
(setq modus-themes-common-palette-overrides
      modus-themes-preset-overrides-intense)

;; Load the theme of choice (built-in themes are always "safe" so they
;; do not need the `no-require' argument of `load-theme').
(load-theme 'modus-operandi)

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

4.2. Sample configuration with and without use-package

What follows is a variant of what we demonstrate in the previous section (Enable and load).

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

;;; For the built-in themes which cannot use `require'.
(use-package emacs
  :config
  (require-theme 'modus-themes) ; `require-theme' is ONLY for the built-in Modus themes

  ;; Add all your customizations prior to loading the themes
  (setq modus-themes-italic-constructs t
        modus-themes-bold-constructs nil)

  ;; Maybe define some palette overrides, such as by using our presets
  (setq modus-themes-common-palette-overrides
        modus-themes-preset-overrides-intense)

  ;; Load the theme of your choice.
  (load-theme 'modus-operandi)
  :bind ("<f5>" . modus-themes-toggle))



;;; For packaged versions which must use `require'.
(use-package modus-themes
  :ensure t
  :demand t
  :config
  ;; Add all your customizations prior to loading the themes
  (setq modus-themes-italic-constructs t
        modus-themes-bold-constructs nil)

  ;; Maybe define some palette overrides, such as by using our presets
  (setq modus-themes-common-palette-overrides
        modus-themes-preset-overrides-intense)

  ;; Load the theme of your choice.
  (load-theme 'modus-operandi :no-confirm)
  :bind ("<f5>" . modus-themes-toggle))

The same without use-package:

(require 'modus-themes) ; OR for the built-in themes: (require-theme 'modus-themes)

;; Add all your customizations prior to loading the themes
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil)

;; Maybe define some palette overrides, such as by using our presets
(setq modus-themes-common-palette-overrides
      modus-themes-preset-overrides-intense)

;; Load the theme of your choice:
(load-theme 'modus-operandi :no-confirm)

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

Differences between loading and enabling.

Note: make sure not to customize the variable custom-theme-load-path or 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.

4.3. Differences between loading and enabling

The reason we recommend load-theme instead of the other option of 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 enable-theme function simply puts an already loaded theme to the top of the list of enabled items, re-using whatever state was last loaded.

As such, 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 custom-set-faces, as well as new values assigned to the options the Modus themes provide (Customization Options).

Our tests show that 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 load-theme brings about does, however, come at the cost of being somewhat slower than 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:

(require 'modus-themes)

;; Activate your desired themes here
(load-theme 'modus-operandi t t)
(load-theme 'modus-vivendi t t)

;; Enable the preferred one
(enable-theme 'modus-operandi)

Toggle themes without reloading them.

Sample configuration with and without use-package.

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

Use theme colors in code with modus-themes-with-colors.

5. Customization options

The Modus themes are highly configurable, though they should work well without any further tweaks. We provide a variety of user options. The following code block provides an overview. In addition to those variables, the themes support a comprehensive system of overrides: it can be used to make thoroughgoing changes to the looks of the themes (Option for palette overrides). We document everything at length in the pages of this manual and also provide ready-to-use code samples.

Remember that all customization options must be evaluated before loading a theme (Enable and load). If the theme is already active, it must be reloaded for changes to take effect.

;; In all of the following, WEIGHT is a symbol such as `semibold',
;; `light', `bold', or anything mentioned in `modus-themes-weights'.
(setq modus-themes-italic-constructs t
      modus-themes-bold-constructs nil
      modus-themes-mixed-fonts t
      modus-themes-variable-pitch-ui nil
      modus-themes-custom-auto-reload t
      modus-themes-disable-other-themes t

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

      ;; The `modus-themes-completions' is an alist that reads two
      ;; keys: `matches', `selection'.  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'   :: `underline', `italic', `WEIGHT'
      ;; `selection' :: `underline', `italic', `WEIGHT'
      modus-themes-completions
      '((matches . (extrabold))
        (selection . (semibold italic text-also)))

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

      ;; The `modus-themes-headings' is an alist: read the manual's
      ;; node about it or its doc string.  Basically, it supports
      ;; per-level configurations for the optional use of
      ;; `variable-pitch' typography, a height value as a multiple of
      ;; the base font size (e.g. 1.5), and a `WEIGHT'.
      modus-themes-headings
      '((1 . (variable-pitch 1.5))
        (2 . (1.3))
        (agenda-date . (1.3))
        (agenda-structure . (variable-pitch light 1.8))
        (t . (1.1))))

;; Remember that more (MUCH MORE) can be done with overrides, which we
;; document extensively in this manual.

5.1. Option for reloading the theme on custom change

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

Symbol: modus-themes-custom-auto-reload (boolean type)

Possible values:

  1. nil
  2. t (default)

All theme user options take effect when a theme is loaded. Any subsequent changes require the theme to be reloaded.

When this variable has a non-nil value, any change made via the Custom UI or related functions such as customize-set-variable and setopt (Emacs 29), will trigger a reload automatically.

With a nil value, changes to user options have no further consequences: the user must manually reload the theme (Enable and load).

5.2. Option for disabling other themes while loading Modus

[ Part of 4.1.0-dev. ]

Brief: Disable all other themes when loading a Modus theme.

Symbol: modus-themes-disable-other-themes (boolean type)

Possible values:

  1. nil
  2. t (default)

When the value is non-nil, the commands modus-themes-toggle and modus-themes-select, as well as the modus-themes-load-theme function, will disable all other themes while loading the specified Modus theme. This is done to ensure that Emacs does not blend two or more themes: such blends lead to awkward results that undermine the work of the designer.

When the value is nil, the aforementioned commands and function will only disable other themes within the Modus collection.

This option is provided because Emacs themes are not necessarily limited to colors/faces: they can consist of an arbitrary set of customizations. Users who use such customization bundles must set this variable to a nil value.

5.3. Option for more bold constructs

Brief: Use bold for code syntax highlighting and related.

Symbol: modus-themes-bold-constructs (boolean type)

Possible values:

  1. nil (default)
  2. t

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

With a non-nil value (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 prompts.

Advanced users may also want to configure the exact attributes of the bold face.

Configure bold and italic faces.

5.4. Option for more italic constructs

Brief: Use italics for code syntax highlighting and related.

Symbol: modus-themes-italic-constructs (boolean type)

Possible values:

  1. nil (default)
  2. t

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

With a non-nil value (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 italic face.

Configure bold and italic faces.

5.5. Option for font mixing

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

Symbol: modus-themes-mixed-fonts (boolean type)

Possible values:

  1. nil (default)
  2. t

When set to non-nil (t), configure some spacing-sensitive faces like Org tables and code blocks to always inherit from the 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 M-x variable-pitch-mode. Otherwise the layout can appear broken, due to how spacing is done.

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

Font configurations for Org and others.

5.6. Option for command prompt styles

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

Symbol: modus-themes-prompts (choice type, list of properties)

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

  • italic
  • italic
  • A font weight, which must be supported by the underlying typeface:
    • thin
    • ultralight
    • extralight
    • light
    • semilight
    • regular
    • medium
    • semibold
    • bold
    • heavy
    • extrabold
    • ultrabold

The default (a nil value or an empty list) means to only use a subtle colored foreground color.

The italic property adds a slant to the font’s forms (italic or oblique forms, depending on the typeface).

The symbol of a font weight attribute such as light, semibold, et cetera, adds the given weight to links. Valid symbols are defined in the variable modus-themes-weights. The absence of a weight means that the one of the underlying text will be used.

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

(bold italic)
(italic semibold)

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

In user configuration files the form may look like this:

(setq modus-themes-prompts '(extrabold italic))

Make prompts more or less colorful.

5.7. Option for completion framework aesthetics

Brief: Set the overall style of completion framework interfaces.

Symbol: modus-themes-completions (alist type properties)

This affects Company, Corfu, Flx, Icomplete/Fido, Ido, Ivy, Orderless, Vertico, and the standard *Completions* buffer. The value is an alist of expressions, each of which takes the form of (KEY . LIST-OF-PROPERTIES). KEY is a symbol, while PROPERTIES is a list. Here is a sample, followed by a description of the particularities:

(setq modus-themes-completions
      '((matches . (extrabold underline))
        (selection . (semibold italic))))

The matches key refers to the highlighted characters that correspond to the user’s input. When its properties are 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:

  • underline to draw a line below the characters;
  • italic to use a slanted font (italic or oblique forms);
  • The symbol of a font weight attribute such as light, semibold, et cetera. Valid symbols are defined in the variable modus-themes-weights. The absence of a weight means that bold will be used.

The selection key applies to the current line or currently matched candidate, depending on the specifics of the user interface. When its properties are 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):

  • underline to draw a line below the characters;
  • italic to use a slanted font (italic or oblique forms);
  • The symbol of a font weight attribute such as light, semibold, et cetera. Valid symbols are defined in the variable modus-themes-weights. The absence of a weight means that bold will be used.

Apart from specifying each key separately, a catch-all 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:

(setq modus-themes-completions
      '((t . (extrabold underline))))

Is the same as:

(setq modus-themes-completions
      '((matches . (extrabold underline))
        (selection . (extrabold underline))))

Make completion matches more or less colorful.

5.8. Option for org-mode block styles

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

Symbol: modus-themes-org-blocks (choice type)

Possible values:

  1. nil (default)
  2. gray-background
  3. tinted-background

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 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. If the begin/end lines do not extend in this way, check the value of the Org user option org-fontify-whole-block-delimiter-line.

Option tinted-background uses a colored background for the contents of the block. The exact color value will depend on the programming language and is controlled by the variable 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 org-mode-restart.

Code blocks use their major mode’s fontification (syntax highlighting) only when the variable org-src-fontify-natively is non-nil. While quote/verse blocks require setting org-fontify-quote-and-verse-blocks to a non-nil value.

Update Org block delimiter fontification.

5.9. Option for the headings' overall style

Brief: Heading styles with optional list of values per heading level.

Symbol: modus-themes-headings (alist type, multiple properties)

This is an alist that accepts a (KEY . LIST-OF-VALUES) combination. The KEY is either a number, representing the heading’s level (0 through 8) or t, which pertains to the fallback style. The named keys agenda-date and agenda-structure apply to the Org agenda.

Level 0 is a special heading: it is used for what counts as a document title or equivalent, such as the #+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 with various stylistic combinations, followed by a presentation of all available properties:

(setq modus-themes-headings
      '((1 . (variable-pitch 1.5))
        (2 . (1.3))
        (agenda-date . (1.3))
        (agenda-structure . (variable-pitch light 1.8))
        (t . (1.1))))

Properties:

  • A font weight, which must be supported by the underlying typeface:
    • thin
    • ultralight
    • extralight
    • light
    • semilight
    • regular
    • medium
    • semibold
    • bold (default)
    • heavy
    • extrabold
    • ultrabold
  • A floating point as a height multiple of the default or a cons cell in the form of (height . FLOAT).

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

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

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

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 (height . FLOAT) or (height FLOAT), where FLOAT is the given number.

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

(semibold)
(variable-pitch semibold 1.3)
(variable-pitch semibold (height 1.3)) ; same as above
(variable-pitch semibold (height . 1.3)) ; same as above

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

In user configuration files the form may look like this:

(setq modus-themes-headings
      '((1 . (variable-pitch 1.5))
        (2 . (1.3))
        (agenda-date . (1.3))
        (agenda-structure . (variable-pitch light 1.8))
        (t . (1.1))))

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

(setq modus-themes-headings
      '((1 . t)           ; keep the default style
        (2 . (semibold 1.2))
        (t . (rainbow)))) ; style for all other headings

(setq modus-themes-headings
      '((1 . (variable-pitch 1.5))
        (2 . (semibold))
        (t . t))) ; default style for all other levels

Note that the text color of headings, of their background, and overline can all be set via the overrides. It is possible to have any color combination for any heading level (something that could not be done in older versions of the themes).

Option for palette overrides.

Make headings more or less colorful.

5.10. Option for variable-pitch font in UI elements

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

Symbol: modus-themes-variable-pitch-ui (boolean type)

Possible values:

  1. nil (default)
  2. t

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

Font configurations for Org and others.

5.11. Option for palette overrides

This section describes palette overrides in detail. For a simpler alternative, use the presets we provide (Palette override presets).

Each Modus theme specifies a color palette that declares named color values and semantic color mappings:

  • Named colors consist of a symbol and a string that specifies a hexadecimal RGB value. For example: (blue-warmer "#354fcf").
  • The semantic color mappings associate an abstract construct with a given named color from the palette, like (heading-2 yellow-faint). Both elements of the list are symbols, though the cadr (value) can be a string that specifies a color, such as (heading-2 "#354fcf").

Both of those subsets can be overridden, thus refashioning the theme. Overrides are either shared, by being stored in the user option modus-themes-common-palette-overrides, or they are specific to the theme they name. In the latter case, the naming scheme of each palette variable is THEME-NAME-palette-overrides, thus yielding:

  • modus-operandi-palette-overrides
  • modus-operandi-deuteranopia-palette-overrides
  • modus-operandi-tinted-palette-overrides
  • modus-vivendi-palette-overrides
  • modus-vivendi-deuteranopia-palette-overrides
  • modus-vivendi-tinted-palette-overrides

Theme-specific overrides take precedence over the shared ones. It is strongly advised that shared overrides do NOT alter color values, as those will not be appropriate for both dark and light themes. Common overrides are best limited to the semantic color mappings as those use the color value that corresponds to the active theme (e.g. make the cursor blue-warmer in all themes, whatever the value of blue-warmer is in each theme).

The value of any overrides’ variable must mirror a theme’s palette. Palette variables are named after their theme as THEME-NAME-palette. For example, the modus-operandi-palette is like this:

(defconst modus-operandi-palette
    '(
;;; Basic values

      (bg-main     "#ffffff")
      (bg-dim      "#f0f0f0")
      (fg-main     "#000000")

      ;; ...

      (red         "#a60000")
      (red-warmer  "#972500")
      (red-cooler  "#a0132f")
      (red-faint   "#7f0000")
      (red-intense "#d00000")

      ;; ...

;;;; Mappings

      ;; ...

      (cursor fg-main)
      (builtin magenta-warmer)
      (comment fg-dim)
      (constant blue-cooler)
      (docstring green-faint)
      (fnname magenta)
      (keyword magenta-cooler)

      ;; ...
      ))

The modus-operandi-palette-overrides targets the entries that need to be changed. For example, to make the main foreground colour a dark gray instead of pure black, use a shade of red for comments, and apply a cyan hue to keywords:

(setq modus-operandi-palette-overrides
      '((fg-main "#333333")
        (comment red-faint)
        (keyword cyan-cooler)))

Changes take effect upon theme reload (Custom reload theme). Overrides are removed by setting their variable to a nil value.

The common accented foregrounds in each palette follow a predictable naming scheme: HUE{,-warmer,-cooler,-faint,-intense}. HUE is one of the six basic colors: red, green, blue, yellow, magenta, cyan.

Named colors that are meant to be used as backgrounds contain bg in their name, such as bg-red-intense. While special purpose foregrounds that are meant to be combined with such backgrounds, contain fg in their name, such as fg-removed which complements bg-removed.

Named colors can be previewed, such as with the command modus-themes-list-colors (Preview theme colors).

For a video tutorial that users of all skill levels can approach, watch: https://protesilaos.com/codelog/2022-12-17-modus-themes-v4-demo/.

5.11.1. Palette override presets

This section shows how to refashion the themes by opting in to the stylistic presets we provide. Those presets override the default color mappings to amplify or tone down the overall coloration of the them.

To make almost all aspects of the themes less intense, use this:

;; Always remember to reload the theme for changes to take effect!
(setq modus-themes-common-palette-overrides modus-themes-preset-overrides-faint)

With modus-themes-preset-overrides-faint the grays are toned down, gray backgrounds are removed from some contexts, and almost all accent colors are desaturated. It makes the themes less attention-grabbing.

On the opposite end of the stylistic spectrum, we have this

;; Always remember to reload the theme for changes to take effect!
(setq modus-themes-common-palette-overrides modus-themes-preset-overrides-intense)

The modus-themes-preset-overrides-intense makes many background colors accented instead of gray and increases coloration in a number of places. Colors stand out more and are made easier to spot.

Note that the user is not limited to those presets. The system of overrides we provide makes it possible to tweak the value of each individual named color and to change how values are assigned to semantic color mappings (Option for palette overrides). Subsequent sections provide examples (Stylistic variants using palette overrides).

It is also possible to use those presets as a basis and, for example, add to them code from the subsequent sections of this manual. This is the general idea (extra space for didactic purposes):

(setq modus-themes-common-palette-overrides
      `(
        ;; From the section "Make the mode line borderless"
        (border-mode-line-active unspecified)
        (border-mode-line-inactive unspecified)

        ;; From the section "Make matching parenthesis more or less intense"
        (bg-paren-match bg-magenta-intense)
        (underline-paren-match fg-main)

        ;; And expand the preset here.  Note that the ,@ works because
        ;; we use the backtick for this list, instead of a straight
        ;; quote.
        ,@modus-themes-preset-overrides-intense))

5.11.2. Stylistic variants using palette overrides

This section contains practical examples of overriding the palette of the themes (Option for palette overrides). Users can copy the code to their init file, evaluate it, and then re-load the theme for changes to take effect. To apply overrides at startup simply define them before the call that loads the theme. Remember that we also provide presets that are easier to apply (Palette override presets).

5.11.2.1. Make the mode line borderless

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). To hide the border around the active and inactive mode lines, we need to set their color to that of the underlying background.

Make the active mode line colorful.

Add padding to mode line.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Remove the border
(setq modus-themes-common-palette-overrides
      '((border-mode-line-active unspecified)
        (border-mode-line-inactive unspecified)))

;; Keep the border but make it the same color as the background of the
;; mode line (thus appearing borderless).  The difference with the
;; above is that this version is a bit thicker because the border are
;; still there.
(setq modus-themes-common-palette-overrides
      '((border-mode-line-active bg-mode-line-active)
        (border-mode-line-inactive bg-mode-line-inactive)))
5.11.2.2. Make the active mode line colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show some snippets that apply different stylistic variants. Of course, it is possible to use theme-specific overrides to, say, have a blue mode line for modus-operandi and a red one for modus-vivendi.

Make the mode line borderless.

Add padding to mode line.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Blue background, neutral foreground, intense blue border
(setq modus-themes-common-palette-overrides
      '((bg-mode-line-active bg-blue-intense)
        (fg-mode-line-active fg-main)
        (border-mode-line-active blue-intense)))

;; Subtle blue background, neutral foreground, intense blue border
(setq modus-themes-common-palette-overrides
      '((bg-mode-line-active bg-blue-subtle)
        (fg-mode-line-active fg-main)
        (border-mode-line-active blue-intense)))

;; Subtle red background, red foreground, invisible border
(setq modus-themes-common-palette-overrides
      '((bg-mode-line-active bg-red-subtle)
        (fg-mode-line-active red-warmer)
        (border-mode-line-active bg-red-subtle)))
5.11.2.3. Make the tab bar more or less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to affect the colors of the built-in tab-bar-mode and tab-line-mode.

For consistent theme-wide results, consider changing the mode line, fringes, and line numbers. These are shown in other sections of this manual.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Make the `tab-bar-mode' mode subtle while keepings its original
;; gray aesthetic.
(setq modus-themes-common-palette-overrides
      '((bg-tab-bar bg-main)
        (bg-tab-current bg-active)
        (bg-tab-other bg-dim)))

;; Like the above, but the current tab has a colorful background and
;; the inactive tabs have a slightly more noticeable gray background.
(setq modus-themes-common-palette-overrides
      '((bg-tab-bar bg-main)
        (bg-tab-current bg-cyan-intense)
        (bg-tab-other bg-inactive)))

;; Make the tabs colorful, using a monochromatic pattern (e.g. shades
;; of cyan).
(setq modus-themes-common-palette-overrides
      '((bg-tab-bar bg-cyan-nuanced)
        (bg-tab-current bg-cyan-intense)
        (bg-tab-other bg-cyan-subtle)))

;; Like the above, but with a dichromatic pattern (cyan and magenta).
(setq modus-themes-common-palette-overrides
      '((bg-tab-bar bg-cyan-nuanced)
        (bg-tab-current bg-magenta-intense)
        (bg-tab-other bg-cyan-subtle)))
5.11.2.4. Make the fringe invisible or another color

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to make the fringe invisible or how to assign to it a different color. The “fringe” is a small area to the right and left side of the Emacs window which shows indicators such as for truncation or continuation lines.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Make the fringe invisible
(setq modus-themes-common-palette-overrides
      '((fringe unspecified)))

;; Make the fringe more intense
(setq modus-themes-common-palette-overrides
      '((fringe bg-active)))

;; Make the fringe colorful, but nuanced
(setq modus-themes-common-palette-overrides
      '((fringe bg-blue-nuanced)))
5.11.2.5. Make links use subtle or no underlines

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In this example, we showcase the special use of the unspecified symbol that underline mappings can read correctly.

;; Subtle underlines
(setq modus-themes-common-palette-overrides
      '((underline-link border)
        (underline-link-visited border)
        (underline-link-symbolic border)))

;; No underlines
(setq modus-themes-common-palette-overrides
      '((underline-link unspecified)
        (underline-link-visited unspecified)
        (underline-link-symbolic unspecified)))
5.11.2.6. Make prompts more or less colorful

This section contains practical examples of overriding the palette of the themes (Option for palette overrides). In the following code block we show how to add or remove color from prompts.

Option for command prompt styles.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Keep the background unspecified (like the default), but use a faint
;; foreground color.
(setq modus-themes-common-palette-overrides
      '((fg-prompt cyan-faint)
        (bg-prompt unspecified)))

;; Add a nuanced background to prompts that complements their foreground.
(setq modus-themes-common-palette-overrides
      '((fg-prompt cyan)
        (bg-prompt bg-cyan-nuanced)))

;; Add a yellow background and adjust the foreground accordingly.
(setq modus-themes-common-palette-overrides
      '((fg-prompt fg-main)
        (bg-prompt bg-yellow-subtle))) ; try to replace "subtle" with "intense"
5.11.2.7. Make completion matches more or less colorful

This section contains practical examples of overriding the palette of the themes (Option for palette overrides). Here we demonstrate how to activate background coloration for completion matches. We show three different degrees of intensity.

Option for completion framework aesthetics.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Add a nuanced background color to completion matches, while keeping
;; their foreground intact (foregrounds do not need to be specified in
;; this case, but we do it for didactic purposes).
(setq modus-themes-common-palette-overrides
      '((fg-completion-match-0 blue)
        (fg-completion-match-1 magenta-warmer)
        (fg-completion-match-2 cyan)
        (fg-completion-match-3 red)
        (bg-completion-match-0 bg-blue-nuanced)
        (bg-completion-match-1 bg-magenta-nuanced)
        (bg-completion-match-2 bg-cyan-nuanced)
        (bg-completion-match-3 bg-red-nuanced)))

;; Add intense background colors to completion matches and adjust the
;; foregrounds accordingly.
(setq modus-themes-common-palette-overrides
      '((fg-completion-match-0 fg-main)
        (fg-completion-match-1 fg-main)
        (fg-completion-match-2 fg-main)
        (fg-completion-match-3 fg-main)
        (bg-completion-match-0 bg-blue-intense)
        (bg-completion-match-1 bg-yellow-intense)
        (bg-completion-match-2 bg-cyan-intense)
        (bg-completion-match-3 bg-red-intense)))

;; Like the above, but with subtle backgrounds.
(setq modus-themes-common-palette-overrides
      '((fg-completion-match-0 fg-main)
        (fg-completion-match-1 fg-main)
        (fg-completion-match-2 fg-main)
        (fg-completion-match-3 fg-main)
        (bg-completion-match-0 bg-blue-subtle)
        (bg-completion-match-1 bg-yellow-subtle)
        (bg-completion-match-2 bg-cyan-subtle)
        (bg-completion-match-3 bg-red-subtle)))

Adding to the above, it is possible to, say, reduce the number of colors to two:

;; No backgrounds (like the default) and just use two colors.
(setq modus-themes-common-palette-overrides
      '((fg-completion-match-0 blue)
        (fg-completion-match-1 yellow)
        (fg-completion-match-2 blue)
        (fg-completion-match-3 yellow)
        (bg-completion-match-0 unspecified)
        (bg-completion-match-1 unspecified)
        (bg-completion-match-2 unspecified)
        (bg-completion-match-3 unspecified)))

;; Again, a two-color style but this time with backgrounds
(setq modus-themes-common-palette-overrides
      '((fg-completion-match-0 blue)
        (fg-completion-match-1 yellow)
        (fg-completion-match-2 blue)
        (fg-completion-match-3 yellow)
        (bg-completion-match-0 bg-blue-nuanced)
        (bg-completion-match-1 bg-yellow-nuanced)
        (bg-completion-match-2 bg-blue-nuanced)
        (bg-completion-match-3 bg-yellow-nuanced)))

The user can mix and match to their liking.

5.11.2.8. Make comments yellow and strings green

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In previous versions of the themes, we provided an option for yellow-ish comments and green-ish strings. For some users, those were still not good enough, as the exact values were hardcoded. Here we show how to reproduce the effect, but also how to tweak it to one’s liking.

Make code syntax use the old alt-syntax style.

Make use of alternative styles for code syntax.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Yellow comments and green strings like older versions of the Modus
;; themes
(setq modus-themes-common-palette-overrides
      '((comment yellow-cooler)
        (string green-cooler)))

;; Faint yellow comments and a different shade of green for strings
(setq modus-themes-common-palette-overrides
      '((comment yellow-faint)
        (string green-warmer)))

;; Green comments and yellow strings, because now the user has the
;; freedom to do it
(setq modus-themes-common-palette-overrides
      '((comment green)
        (string yellow-cooler)))
5.11.2.9. Make code syntax use the old alt-syntax style

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In this section we show how to reproduce what previous versions of the Modus themes provided as a stylistic alternative for code syntax. The upside of using overrides for this purpose is that we can tweak the style to our liking, but first let’s start with its recreation:

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; The old "alt-syntax"
(setq modus-themes-common-palette-overrides
      '((builtin magenta)
        (comment fg-dim)
        (constant magenta-cooler)
        (docstring magenta-faint)
        (docmarkup green-faint)
        (fnname magenta-warmer)
        (keyword cyan)
        (preprocessor cyan-cooler)
        (string red-cooler)
        (type magenta-cooler)
        (variable blue-warmer)
        (rx-construct magenta-warmer)
        (rx-backslash blue-cooler)))

The “alt-syntax” could optionally use green strings and yellow comments (Make comments yellow and strings green):

;; Same as above, but with yellow comments and green strings
(setq modus-themes-common-palette-overrides
      '((builtin magenta)
        (comment yellow-faint)
        (constant magenta-cooler)
        (docstring green-faint)
        (docmarkup magenta-faint)
        (fnname magenta-warmer)
        (keyword cyan)
        (preprocessor cyan-cooler)
        (string green-cooler)
        (type magenta-cooler)
        (variable blue-warmer)
        (rx-construct magenta-warmer)
        (rx-backslash blue-cooler)))

The standard “alt-syntax” has red strings. As such, it is interesting to experiment with faintly red colored comments:

;; Like the old "alt-syntax" but with faint red comments
(setq modus-themes-common-palette-overrides
      '((builtin magenta)
        (comment red-faint)
        (constant magenta-cooler)
        (docstring magenta-faint)
        (docmarkup green-faint)
        (fnname magenta-warmer)
        (keyword cyan)
        (preprocessor cyan-cooler)
        (string red-cooler)
        (type magenta-cooler)
        (variable blue-warmer)
        (rx-construct magenta-warmer)
        (rx-backslash blue-cooler)))

The user can always mix and match styles to their liking.

Make use of alternative styles for code syntax.

5.11.2.10. Make use of alternative styles for code syntax

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). The idea here is to change how named colors are mapped to code syntax. Each of the following snippets give the modus-themes a different feel while editing code.

Note that my modus-themes and ef-themes do not use the same palettes, so some things are different. If you copy from the latter to the former, double-check that the entries exist in the given Modus theme palette.

Make comments yellow and strings green.

Make code syntax use the old alt-syntax style.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Mimic `ef-night' theme (from my `ef-themes') for code syntax
;; highlighting, while still using the Modus colors (and other
;; mappings).
(setq modus-themes-common-palette-overrides
      '((builtin green-cooler)
        (comment yellow-faint)
        (constant magenta-cooler)
        (fnname cyan-cooler)
        (keyword blue-warmer)
        (preprocessor red-warmer)
        (docstring cyan-faint)
        (string blue-cooler)
        (type magenta-cooler)
        (variable cyan)))

;; Mimic `ef-summer' theme (from my `ef-themes') for code syntax
;; highlighting, while still using the Modus colors (and other
;; mappings).
(setq modus-themes-common-palette-overrides
      '((builtin magenta)
        (comment yellow-faint)
        (constant red-cooler)
        (fnname magenta-warmer)
        (keyword magenta-cooler)
        (preprocessor green-warmer)
        (docstring cyan-faint)
        (string yellow-warmer)
        (type cyan-warmer)
        (variable blue-warmer)))

;; Mimic `ef-bio' theme (from my `ef-themes') for code syntax
;; highlighting, while still using the Modus colors (and other
;; mappings).
(setq modus-themes-common-palette-overrides
      '((builtin green)
        (comment yellow-faint)
        (constant blue)
        (fnname green-warmer)
        (keyword green-cooler)
        (preprocessor green)
        (docstring green-faint)
        (string magenta-cooler)
        (type cyan-warmer)
        (variable blue-warmer)))

;; Mimic `ef-trio-light' theme (from my `ef-themes') for code syntax
;; highlighting, while still using the Modus colors (and other
;; mappings).
(setq modus-themes-common-palette-overrides
      '((builtin magenta-cooler)
        (comment yellow-faint)
        (constant magenta-warmer)
        (fnname blue-warmer)
        (keyword magenta)
        (preprocessor red-cooler)
        (docstring magenta-faint)
        (string green-cooler)
        (type cyan-cooler)
        (variable cyan-warmer)))
5.11.2.11. Make matching parenthesis more or less intense

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In this code block we show how to change the background of matching delimiters when show-paren-mode is enabled. We also demonstrate how to enable underlines for those highlights.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Change the background to a shade of magenta
(setq modus-themes-common-palette-overrides
      '((bg-paren-match bg-magenta-intense)))

;; Enable underlines by applying a color to them
(setq modus-themes-common-palette-overrides
      '((bg-paren-match bg-magenta-intense)
        (underline-paren-match fg-main)))
5.11.2.12. Make box buttons more or less gray

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). By default, the boxed buttons that appear in M-x customize and related are distinct shades of gray. The following set of overrides removes the gray from the active buttons and amplifies it for the inactive ones.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

(setq modus-themes-common-palette-overrides
      '((bg-button-active bg-main)
        (fg-button-active fg-main)
        (bg-button-inactive bg-inactive)
        (fg-button-inactive "gray50")))
5.11.2.13. Make TODO and DONE more or less intense

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to affect just the TODO and DONE keywords that we encounter in Org buffers. The idea is to make those pop out more or to subdue them.

Make headings more or less colorful.

Make inline code in prose use alternative styles.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Increase intensity
(setq modus-themes-common-palette-overrides
      '((prose-done green-intense)
        (prose-todo red-intense)))

;; Tone down intensity
(setq modus-themes-common-palette-overrides
      '((prose-done green-faint)   ; OR replace `green-faint' with `olive'
        (prose-todo red-faint)))   ; OR replace `red-faint' with `rust'

;; Keep TODO at its default (so no override for it), but make DONE
;; gray.
(setq modus-themes-common-palette-overrides
      '((prose-done fg-dim)))
5.11.2.14. Make headings more or less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to alter the looks of headings, such as in Org mode. Using overrides here offers far more flexibility than what we could achieve with previous versions of the themes: the user can mix and match styles at will.

Make TODO and DONE more intense.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Apply more colorful foreground to some headings (headings 0-8).
;; Level 0 is for Org #+title and related.
(setq modus-themes-common-palette-overrides
      '((fg-heading-1 blue-warmer)
        (fg-heading-2 yellow-cooler)
        (fg-heading-3 cyan-cooler)))

;; Like the above, but with gradient colors
(setq modus-themes-common-palette-overrides
      '((fg-heading-1 blue)
        (fg-heading-2 cyan)
        (fg-heading-3 green)))

;; Add color to level 1 heading, but use the main foreground for
;; others
(setq modus-themes-common-palette-overrides
      '((fg-heading-1 blue)
        (fg-heading-2 fg-main)
        (fg-heading-3 fg-main)))

;; Apply colorful foreground, background, and overline (headings 0-8)
(setq modus-themes-common-palette-overrides
      '((fg-heading-1 blue-warmer)
        (bg-heading-1 bg-blue-nuanced)
        (overline-heading-1 blue)))

;; Apply gray scale foreground, background, and overline (headings 0-8)
(setq modus-themes-common-palette-overrides
      '((fg-heading-1 fg-main)
        (bg-heading-1 bg-dim)
        (overline-heading-1 border)))
5.11.2.15. Make Org agenda more or less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we provide three distinct code blocks. The first adds alternative and more varied colors to the Org agenda (and related). The second uses faint coloration. The third makes the agenda use various shades of blue. Mix and match at will, while also combining these styles with what we show in the other chapters with practical stylistic variants.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.

;; Make the Org agenda use alternative and varied colors.
(setq modus-themes-common-palette-overrides
      '((date-common cyan)   ; default value (for timestamps and more)
        (date-deadline red-warmer)
        (date-event magenta-warmer)
        (date-holiday blue) ; for M-x calendar
        (date-now yellow-warmer)
        (date-scheduled magenta-cooler)
        (date-weekday cyan-cooler)
        (date-weekend blue-faint)))

An example with faint coloration:

;; Make the Org agenda use faint colors.
(setq modus-themes-common-palette-overrides
      '((date-common cyan-faint) ; for timestamps and more
        (date-deadline red-faint)
        (date-event fg-alt) ; default
        (date-holiday magenta) ; default (for M-x calendar)
        (date-now fg-main) ; default
        (date-scheduled yellow-faint)
        (date-weekday fg-dim)
        (date-weekend fg-dim)))

A third example that makes the agenda more blue:

;; Make the Org agenda use more blue instead of yellow and red.
(setq modus-themes-common-palette-overrides
      '((date-common cyan) ; default value (for timestamps and more)
        (date-deadline blue-cooler)
        (date-event blue-faint)
        (date-holiday blue) ; for M-x calendar
        (date-now blue-faint)
        (date-scheduled blue)
        (date-weekday fg-main)
        (date-weekend fg-dim)))
5.11.2.16. Make inline code in prose use alternative styles

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In the following code block we show how to affect constructs such as Org’s verbatim, code, and macro entries. We also provide mappings for tables, property drawers, tags, and code block delimiters, though we do not show every possible permutation.

Make TODO and DONE more or less intense.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; These are all the mappings at their default values for didactic
;; purposes
(setq modus-themes-common-palette-overrides
      '((prose-block fg-dim)
        (prose-code green-cooler)
        (prose-done green)
        (prose-macro magenta-cooler)
        (prose-metadata fg-dim)
        (prose-metadata-value fg-alt)
        (prose-table fg-alt)
        (prose-tag magenta-faint)
        (prose-todo red)
        (prose-verbatim magenta-warmer)))

;; Make code block delimiters use a shade of red, tone down verbatim,
;; code, and macro, and amplify the style of property drawers
(setq modus-themes-common-palette-overrides
      '((prose-block red-faint)
        (prose-code fg-dim)
        (prose-macro magenta-faint)
        (prose-metadata cyan)
        (prose-metadata-value green-warmer)
        (prose-verbatim fg-dim)))

;; Like the above but with more color variety for the inline code
;; elements
(setq modus-themes-common-palette-overrides
      '((prose-block red-faint)
        (prose-code blue-cooler)
        (prose-macro yellow-warmer)
        (prose-metadata cyan)
        (prose-metadata-value green-warmer)
        (prose-verbatim red-warmer)))
5.11.2.17. Make mail citations and headers more or less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In this section we show how to change the coloration of email message headers and citations. Before we show the code, this is the anatomy of a message:

From: Protesilaos <info@protesilaos.com>
To: Modus-Themes Development <~protesilaos/modus-themes@lists.sr.ht>
Subject: Test subject
--- Headers above this line; message and citations below ---
This is some sample text

> > Older quote
> Newer quote

We thus have the following:

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Reduce the intensity of mail citations and headers
(setq modus-themes-common-palette-overrides
      '((mail-cite-0 cyan-faint)
        (mail-cite-1 yellow-faint)
        (mail-cite-2 green-faint)
        (mail-cite-3 red-faint)
        (mail-part olive)
        (mail-recipient indigo)
        (mail-subject maroon)
        (mail-other slate)))

;; Make mail citations more intense; adjust the headers accordingly
(setq modus-themes-common-palette-overrides
      '((mail-cite-0 blue)
        (mail-cite-1 yellow)
        (mail-cite-2 green)
        (mail-cite-3 magenta)
        (mail-part magenta-cooler)
        (mail-recipient cyan)
        (mail-subject red-warmer)
        (mail-other cyan-cooler)))

;; Make all citations faint and neutral; make most headers green but
;; use red for the subject lie so that it stands out
(setq modus-themes-common-palette-overrides
      '((mail-cite-0 fg-dim)
        (mail-cite-1 fg-alt)
        (mail-cite-2 fg-dim)
        (mail-cite-3 fg-alt)
        (mail-part yellow-cooler)
        (mail-recipient green-cooler)
        (mail-subject red-cooler)
        (mail-other green)))
5.11.2.18. Make the region preserve text colors, plus other styles

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to make the region respect the underlying text colors or how to make the background more/less intense while combining it with an appropriate foreground value.

Do not extend the region background.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; A background with no specific foreground (use foreground of
;; underlying text)
(setq modus-themes-common-palette-overrides
      '((bg-region bg-ochre) ; try to replace `bg-ochre' with `bg-lavender', `bg-sage'
        (fg-region unspecified)))

;; Subtle gray with a prominent blue foreground
(setq modus-themes-common-palette-overrides
      '((bg-region bg-dim)
        (fg-region blue-cooler)))

;; Intense magenta background combined with the main foreground
(setq modus-themes-common-palette-overrides
      '((bg-region bg-magenta-intense)
        (fg-region fg-main)))
5.11.2.19. Make mouse highlights more or less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In the following code block we show how to affect the semantic color mapping that covers mouse hover effects and related highlights:

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Make the background an intense yellow
(setq modus-themes-common-palette-overrides
      '((bg-hover bg-yellow-intense)))

;; Make the background subtle green
(setq modus-themes-common-palette-overrides
      '((bg-hover bg-green-subtle)))
5.11.2.20. Make language underlines less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to affect the color of the underlines that are used by code linters and prose spell checkers.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Make the underlines less intense
(setq modus-themes-common-palette-overrides
      '((underline-err red-faint)
        (underline-warning yellow-faint)
        (underline-note cyan-faint)))

;; Change the color-coding of the underlines
(setq modus-themes-common-palette-overrides
      '((underline-err yellow-intense)
        (underline-warning magenta-intense)
        (underline-note green-intense)))
5.11.2.21. Make line numbers use alternative styles

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). In this section we show how to affect the display-line-numbers-mode.

;; These overrides are common to all Modus themes.  We also provide
;; theme-specific options, such as `modus-operandi-palette-overrides'.
;;
;; In general, the theme-specific overrides are better for overriding
;; color values, such as redefining what `blue-faint' looks like.  The
;; common overrides are best used for changes to semantic color
;; mappings, as we show below.


;; Make line numbers less intense
(setq modus-themes-common-palette-overrides
      '((fg-line-number-inactive "gray50")
        (fg-line-number-active fg-main)
        (bg-line-number-inactive unspecified)
        (bg-line-number-active unspecified)))

;; Like the above, but use a shade of red for the current line number
(setq modus-themes-common-palette-overrides
      '((fg-line-number-inactive "gray50")
        (fg-line-number-active red-cooler)
        (bg-line-number-inactive unspecified)
        (bg-line-number-active unspecified)))

;; Make all numbers more intense, use a more pronounce gray
;; background, and make the current line have a colored background
(setq modus-themes-common-palette-overrides
      '((fg-line-number-inactive fg-main)
        (fg-line-number-active fg-main)
        (bg-line-number-inactive bg-inactive)
        (bg-line-number-active bg-cyan-intense)))

6. 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 (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”.

6.1. More accurate colors in 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 toe -a | grep direct to get a list of relevant terminfo entries. There should be items such as xterm-direct, alacritty-direct, kitty-direct. Once you find the one that corresponds to your terminal, call Emacs with an environment variable like TERM=xterm-direct. Example that can be adapted to shell aliases:

TERM=xterm-direct emacsclient -nw

Another example that can be bound to a key:

TERM=xterm-direct uxterm -e emacsclient -nw

6.2. Range of color with 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 (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 termcol0 entry and a pure white for termcol15. Emacs cannot set the correct background (white for modus-operandi; black for 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 (Preview theme colors):

! 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

6.3. Preview theme colors

The command modus-themes-list-colors prompts for a choice between modus-operandi and modus-vivendi to produce a help buffer that shows a preview of the named colors in the given theme’s palette. The command modus-themes-list-colors-current skips the prompt, using the current Modus theme.

When called with a prefix argument (C-u with the default key bindings), these commands will show a preview of the palette’s semantic color mappings instead of the named colors.

In this context, “named colors” are entries that associate a symbol to a string color value, such as (blue-warmer "#354fcf"). Whereas “semantic color mappings” associate a named color to a symbol, like (string blue-warmer), thus making the theme render all string constructs in the blue-warmer color value (Option for palette overrides).

Aliases for those commands are modus-themes-preview-colors and modus-themes-preview-colors-current.

Each row shows a foreground and background coloration using the underlying value it references. For example a line with #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 and what the contents are, such as *modus-operandi-list-colors* for named colors and =*modus-operandi-list-mappings* for the semantic color mappings.

6.4. 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).

(defun my-demo-modus-operandi ()
  (interactive)
  (setq modus-themes-bold-constructs t) ; ENABLE bold
  (modus-themes-load-theme 'modus-operandi))

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

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

Then assign 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 modus-themes-toggle and relevant functions.

6.5. Get a single color from the palette

[ Part of 4.1.0-dev. ]

Use theme colors in code with modus-themes-with-colors.

The fuction modus-themes-get-color-value can be called from Lisp to return the value of a color from the active Modus theme palette. It takea a COLOR argument and an optional OVERRIDES.

COLOR is a symbol that represents a named color entry in the palette.

Preview theme colors.

If the value is the name of another color entry in the palette (so a mapping), this function recurs until it finds the underlying color value.

With an optional OVERRIDES argument as a non-nil value, it accounts for palette overrides. Else it reads only the default palette.

If COLOR is not present in the palette, this function returns the unspecified symbol, which is safe when used as a face attribute’s value.

An example with modus-operandi to show how this function behaves with/without overrides and when recursive mappings are introduced.

;; Here we show the recursion of palette mappings.  In general, it is
;; better for the user to specify named colors to avoid possible
;; confusion with their configuration, though those still work as
;; expected.
(setq modus-themes-common-palette-overrides
      '((cursor red)
        (fg-mode-line-active cursor)
        (border-mode-line-active fg-mode-line-active)))

;; Ignore the overrides and get the original value.
(modus-themes-get-color-value 'border-mode-line-active)
;; => "#5a5a5a"

;; Read from the overrides and deal with any recursion to find the
;; underlying value.
(modus-themes-get-color-value 'border-mode-line-active :overrides)
;; => "#a60000"

6.6. Use theme colors in code with modus-themes-with-colors

Get a single color from the palette.

Note that users most probably do not need the following. Just rely on the comprehensive overrides we provide (Option for palette overrides).

Advanced users may want to apply colors from the palette of the active Modus theme in their custom code. The modus-themes-with-colors macro supplies those to any form called inside of it. For example:

(modus-themes-with-colors
  (list blue-warmer magenta-cooler fg-added warning variable fg-heading-4))
;; => ("#354fcf" "#531ab6" "#005000" "#884900" "#005e8b" "#721045")

The above return value is for modus-operandi when that is the active theme. Switching to another theme and evaluating this code anew will give us the relevant results for that theme (remember that since version 4, the Modus themes consist of six items (Overview)). The same with modus-vivendi as the active theme:

(modus-themes-with-colors
  (list blue-warmer magenta-cooler fg-added warning variable fg-heading-4))
;; => ("#79a8ff" "#b6a0ff" "#a0e0a0" "#fec43f" "#00d3d0" "#feacd0")

The modus-themes-with-colors has access to the whole palette of the active theme, meaning that it can instantiate both (i) named colors like blue-warmer and (ii) semantic color mappings like warning. We provide commands to inspect those (Preview theme colors).

Others sections in this manual show how to use the aforementioned macro (Advanced customization).

Because the modus-themes-with-colors will most likely be used to customize faces, note that any function that calls it must be run at startup after the theme loads. The same function must also be assigned to the modus-themes-after-load-theme-hook for its effects to persist and be updated when switching between Modus themes (e.g. to update the exact value of blue-warmer when toggling between modus-operandi to modus-vivendi.

6.7. Do not extend the region background

By the default, the background of the region face extends from the end of the line to the edge of the window. To limit it to the end of the line, we need to override the face’s :extend attribute. Adding this to the Emacs configuration file will suffice:

;; Do not extend `region' background past the end of the line.
(custom-set-faces
 '(region ((t :extend nil))))

Make the region preserve text colors, plus other styles.

6.8. Add padding to mode line

Emacs faces do not have a concept of “padding” for the space between the text and its box boundaries. We can approximate the effect by adding a :box attribute, making its border several pixels thick, and using the mode line’s background color for it. This way the thick border will not stand out and will appear as a continuation of the mode line.

Use theme colors in code with modus-themes-with-colors.

(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     ;; Add "padding" to the mode lines
     `(mode-line ((,c :box (:line-width 10 :color ,bg-mode-line-active))))
     `(mode-line-inactive ((,c :box (:line-width 10 :color ,bg-mode-line-inactive)))))))

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

The above has the effect of removing the border around the mode lines. In older versions of the themes, we provided the option for a padded mode line which could also have borders around it. Those were not real border, however, but an underline and an overline. Adjusting the above:

(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     ;; Add "padding" to the mode lines
     `(mode-line ((,c :underline ,border-mode-line-active
                      :overline ,border-mode-line-active
                      :box (:line-width 10 :color ,bg-mode-line-active))))
     `(mode-line-inactive ((,c :underline ,border-mode-line-inactive
                               :overline ,border-mode-line-inactive
                               :box (:line-width 10 :color ,bg-mode-line-inactive)))))))

;; ESSENTIAL to make the underline move to the bottom of the box:
(setq x-underline-at-descent-line t)

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

The reason we no longer provide this option is because it depends on a non-nil value for x-underline-at-descent-line. That variable affects ALL underlines, including those of links. The effect is intrusive and looks awkard in prose.

As such, the Modus themes no longer provide that option but instead offer this piece of documentation to make the user fully aware of the state of affairs.

6.9. Remap face with local value

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 hl-line-mode, but we wish to keep it distinct from other buffers. This is where face-remap-add-relative can be applied and may be combined with modus-themes-with-colors to deliver consistent results.

Use theme colors in code with modus-themes-with-colors.

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

(defvar my-rainbow-region-colors
  (modus-themes-with-colors
    `((red . ,bg-red-subtle)
      (green . ,bg-green-subtle)
      (yellow . ,bg-yellow-subtle)
      (blue . ,bg-blue-subtle)
      (magenta . ,bg-magenta-subtle)
      (cyan . ,bg-cyan-subtle)))
  "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))))

When 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 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:

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

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

Whenever we enter a 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.

6.10. Font configurations for Org and others

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

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 fixed-pitch face.

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

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

[ The fontaine package on GNU ELPA (by Protesilaos) is designed to handle this case. ]

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

;; 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)

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

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

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

Configure bold and italic faces.

Note the differences in the :height property. The default face must specify an absolute value, which is the point size × 10. So if you want to use a font at point size 11, you set the height to 110.1 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 text-scale-adjust command which only operates on the base font size (i.e. the default face’s absolute height).

Note for EWW and Elfeed fonts.

6.11. Configure bold and italic faces

The Modus themes do not hardcode a :weight or :slant attribute in the thousands of faces they cover. Instead, they configure the generic faces called bold and 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 bold and italic faces. Cases where that can be useful include:

  • 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.
  • 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 bold use a semibold weight.
  • 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 italic face.

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.

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):

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

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

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

To reset the font family, one can use this:

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

To ensure that the effects persist after switching between the Modus themes (such as with M-x modus-themes-toggle), the user needs to write their configurations to a function and pass it to the 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).

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 custom-set-faces function: set-face-attribute works just fine, though it probably is better suited for quick previews or for smaller scale operations (custom-set-faces follows the format used in the source code of the themes, which can make it easier to redefine faces in bulk).

;; 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)

Use theme colors in code with modus-themes-with-colors.

6.12. Custom Org todo keyword and priority faces

Users of org-mode have the option to configure various keywords and priority cookies to better match their workflow. User options are org-todo-keyword-faces and 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 org-mode is active requires re-initialization of the mode with 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:

(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)")))

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 org-todo face (in case there is a difference between the two):

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

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

If you want back the defaults, try specifying just the org-todo face:

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

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 org-todo has a background and a foreground, while 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 keyword . face will suffice.

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

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

To find all the faces that are loaded in your current Emacs session, use M-x list-faces-display. Try 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.

Check color combinations.

6.13. Custom Org emphasis faces

Org provides the user option 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:

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

With the exception of org-verbatim and org-code faces, everything else uses the corresponding type of emphasis: a bold typographic weight, or italicised, 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 bold face with a red foreground value (so it colorises the text in addition to the bold weight):

(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.")

This face definition reads as follows:

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

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

(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.")

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:

(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.")

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

(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.")

It is possible to combine those effects:

(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.")

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

Visualize the active Modus theme’s palette.

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

(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)))

That’s it! For changes to take effect in already visited Org files, invoke M-x org-mode-restart.

6.14. Update Org block delimiter fontification

As noted in the section about 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 (Option for org-mode block styles). The variable is 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:

(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)

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

(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)))

6.15. Measure color contrast

The themes provide the functions modus-themes-wcag-formula and modus-themes-contrast. The former is a direct implementation of the WCAG formula: 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 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):

;; 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

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:

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

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 org-mode or 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:

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

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 customize the theme’s color palette.

6.16. Load theme depending on time of day

While we do provide 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 solar.el and then configuring the circadian package:

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

(use-package circadian                  ; you need to install this
  :ensure t
  :after solar
  :config
  (setq circadian-themes '((:sunrise . modus-operandi)
                           (:sunset  . modus-vivendi)))
  (circadian-setup))

6.17. Backdrop for pdf-tools

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, 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 default face.

Remap face with local value.

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

(defun my-pdf-tools-backdrop ()
  (modus-themes-with-colors
    (face-remap-add-relative
     'default
     `(:background ,bg-dim))))

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

The idea is to assign that function to a hook that gets called when pdf-tools renders the document: 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 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 pdf-view-midnight-minor-mode. To which end we arrive at something like the following, which builds on the above example:

(defun my-pdf-tools-backdrop ()
  (modus-themes-with-colors
    (face-remap-add-relative
     'default
     `(:background ,bg-dim))))

(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)

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

6.18. Toggle themes without reloading them

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 enable-theme instead of load-theme:

(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"))))

Differences between loading and enabling.

Recall that modus-themes-toggle uses load-theme.

6.19. 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 modus-themes-after-load-theme-hook, which runs after the modus-themes-load-theme function (used by the command modus-themes-toggle). 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:

(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)

This creates the after-enable-theme-hook and makes it run after each call to 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 modus-themes-toggle and the others mentioned above. enable-theme is called internally by load-theme, so the hook works everywhere.

The downside of the theme-agnostic hook is that any functions added to it will likely not be able to benefit from macro calls that read the active theme, such as modus-themes-with-colors. Not all Emacs themes have the same capabilities.

In this document, we cover modus-themes-after-load-theme-hook though the user can replace it with after-enable-theme-hook should they need to (provided they understand the implications).

6.20. Custom hl-todo colors

The hl-todo package provides the user option 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:

(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)

Or include a let form, if needed:

(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)

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

6.21. Add support for solaire-mode

The 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 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 modus-operandi or 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, 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:

Advanced customization.

Use theme colors in code with modus-themes-with-colors.

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

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

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

7. 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.

7.1. Full support for packages or face groups

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 * tend to have lots of extensions, so the “full support” may not be 100% true…

  • ace-window
  • agda2-mode
  • all-the-icons
  • all-the-icons-dired
  • all-the-icons-ibuffer
  • annotate
  • ansi-color
  • anzu
  • auctex and TeX
  • auto-dim-other-buffers
  • avy
  • bbdb
  • binder
  • bongo
  • boon
  • bookmark
  • calendar and diary
  • centaur-tabs
  • change-log and log-view (such as vc-print-log, vc-print-root-log)
  • chart
  • cider
  • circe
  • citar
  • clojure-mode
  • column-enforce-mode
  • company-mode*
  • compilation-mode
  • completions
  • consult
  • corfu
  • corfu-quick
  • counsel*
  • cperl-mode
  • crontab-mode
  • css-mode
  • csv-mode
  • ctrlf
  • custom (what you get with M-x customize)
  • deadgrep
  • deft
  • devdocs
  • dictionary
  • diff-hl
  • diff-mode
  • dim-autoload
  • dired
  • dired-async
  • dired-git
  • dired-git-info
  • dired-narrow
  • dired-subtree
  • diredfl
  • display-fill-column-indicator-mode
  • doom-modeline
  • ediff
  • ein (Emacs IPython Notebook)
  • eglot
  • el-search
  • eldoc-box
  • elfeed
  • elfeed-score
  • elpher
  • embark
  • ement
  • emms
  • enh-ruby-mode (enhanced-ruby-mode)
  • epa
  • erc
  • ert
  • eshell
  • eshell-fringe-status
  • evil* (evil-mode)
  • eww
  • exwm
  • eyebrowse
  • flycheck
  • flycheck-color-mode-line
  • flycheck-indicator
  • flymake
  • flyspell
  • flx
  • focus
  • fold-this
  • font-lock (generic syntax highlighting)
  • geiser
  • git-commit
  • git-gutter (and variants)
  • git-rebase
  • git-timemachine
  • gnus
  • gotest
  • golden-ratio-scroll-screen
  • helpful
  • highlight-numbers
  • highlight-parentheses (Note on highlight-parentheses.el)
  • highlight-thing
  • hl-fill-column
  • hl-line-mode
  • hl-todo
  • hydra
  • ibuffer
  • icomplete
  • ido-mode
  • iedit
  • iflipb
  • image-dired
  • imenu-list
  • indium
  • info
  • info+ (info-plus)
  • info-colors
  • ioccur
  • isearch, occur, etc.
  • ivy*
  • ivy-posframe
  • jira (org-jira)
  • journalctl-mode
  • js2-mode
  • julia
  • kaocha-runner
  • keycast
  • ledger-mode
  • leerzeichen
  • line numbers (display-line-numbers-mode and global variant)
  • magit
  • make-mode
  • man
  • marginalia
  • markdown-mode
  • markup-faces (adoc-mode)
  • messages
  • minimap
  • mode-line
  • mood-line
  • moody
  • mpdel
  • mu4e
  • multiple-cursors
  • neotree
  • notmuch
  • num3-mode
  • nxml-mode
  • olivetti
  • orderless
  • org*
  • org-journal
  • org-noter
  • org-pomodoro
  • org-recur
  • org-roam
  • org-superstar
  • org-table-sticky-header
  • org-tree-slide
  • origami
  • outline-mode
  • outline-minor-faces
  • package (what you get with M-x list-packages)
  • page-break-lines
  • pandoc-mode
  • paren-face
  • pass
  • pdf-tools
  • persp-mode
  • perspective
  • popup
  • powerline
  • prism (Note for prism.el)
  • prescient
  • proced
  • prodigy
  • pulse
  • pyim
  • quick-peek
  • rainbow-delimiters
  • rcirc
  • rcirc-color
  • recursion-indicator
  • regexp-builder (also known as re-builder)
  • rg (rg.el)
  • ripgrep
  • rmail
  • ruler-mode
  • sesman
  • shell-script-mode
  • shortdoc
  • show-paren-mode
  • shr
  • side-notes
  • sieve-mode
  • skewer-mode
  • slime (slbd)
  • sly
  • smart-mode-line
  • smerge
  • speedbar
  • spell-fu
  • stripes
  • suggest
  • switch-window
  • swiper
  • sx
  • symbol-overlay
  • syslog-mode
  • tab-bar-mode
  • tab-line-mode
  • table (built-in table.el)
  • telega
  • terraform-mode
  • term
  • textsec
  • transient (pop-up windows such as Magit’s)
  • trashed
  • tree-sitter
  • tty-menu
  • tuareg
  • typescript
  • undo-tree
  • vc (vc-dir.el, vc-hooks.el)
  • vertico
  • vertico-quick
  • vimish-fold
  • visible-mark
  • visual-regexp
  • vterm
  • vundo
  • wcheck-mode
  • web-mode
  • wgrep
  • which-function-mode
  • which-key
  • whitespace-mode
  • window-divider-mode
  • writegood-mode
  • woman
  • xah-elisp-mode
  • xterm-color (and ansi-colors)
  • yaml-mode
  • yasnippet

Plus many other miscellaneous faces that are provided by Emacs.

7.2. Indirectly covered 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.

  • ag
  • apropos
  • apt-sources-list
  • bbdb
  • bm
  • breakpoint (provided by the built-in gdb-mi.el library)
  • buffer-expose
  • bufler
  • counsel-notmuch
  • counsel-org-capture-string
  • dashboard (emacs-dashboard)
  • define-word
  • denote
  • disk-usage
  • dtache
  • dynamic-ruler
  • easy-kill
  • ebdb
  • edit-indirect
  • egerrit
  • elfeed-summary
  • evil-owl
  • flyspell-correct
  • fortran-mode
  • freeze-it
  • forge
  • git-walktree
  • goggles
  • highlight-defined
  • highlight-escape-sequences (hes-mode)
  • icomplete-vertical
  • i3wm-config-mode
  • lin
  • minibuffer-line
  • no-emoji
  • org-remark
  • parrot
  • perl-mode
  • php-mode
  • pulsar
  • rjsx-mode
  • side-hustle
  • spell-fu
  • swift-mode
  • tab-bar-echo-area
  • tide
  • undo-hl
  • vdiff
  • vertico-indexed
  • vertico-mouse
  • xref

8. Notes on individual packages

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

8.1. Note on calendar.el weekday and weekend colors

By default, the 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 calendar-weekend-days to either use gray of weekdays or the faint red of weekends uniformly.

;; 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))

For changes to take effect, the Calendar buffer needs to be generated anew.

8.2. Note on git-gutter in Doom Emacs

The git-gutter and 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:

Advanced customization.

Use theme colors in code with modus-themes-with-colors.

(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     ;; Make foreground the same as background for a uniform bar on
     ;; Doom Emacs.
     ;;
     ;; Doom should not be implementing such hacks because themes
     ;; cannot support them:
     ;; <https://protesilaos.com/codelog/2022-08-04-doom-git-gutter-modus-themes/>.
     `(git-gutter-fr:added ((,c :foreground ,bg-added-intense)))
     `(git-gutter-fr:deleted ((,c :foreground ,bg-removed-intense)))
     `(git-gutter-fr:modified ((,c :foreground ,bg-changed-intense))))))

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

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

If the above does not work, try this instead:

(after! modus-themes
  (modus-themes-with-colors
    (custom-set-faces
     ;; Make foreground the same as background for a uniform bar on
     ;; Doom Emacs.
     ;;
     ;; Doom should not be implementing such hacks because themes
     ;; cannot support them:
     ;; <https://protesilaos.com/codelog/2022-08-04-doom-git-gutter-modus-themes/>.
     `(git-gutter-fr:added ((,c :foreground ,bg-added-intense)))
     `(git-gutter-fr:deleted ((,c :foreground ,bg-removed-intense)))
     `(git-gutter-fr:modified ((,c :foreground ,bg-changed-intense))))))

8.3. 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 php-mode package use the font-lock-doc-face instead of font-lock-comment-face.

This seems to make all comments use the appropriate face:

(defun my-multine-comments ()
  (setq-local c-doc-face-name 'font-lock-comment-face))

(add-hook 'php-mode-hook #'my-multine-comments)

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

8.4. 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):

(setq compilation-message-face nil)

If some element of differentiation is still desired, a good option is to render the affected text with the italic face:

(setq compilation-message-face 'italic)

Configure bold and italic faces.

8.5. Note on inline Latex in Org buffers

Org can work with inline latex and related syntax. To actually fontify those constructs, set the variable org-highlight-latex-and-related to the desired list of values (per its doc string). For example:

(setq org-highlight-latex-and-related '(latex script))

Remember to use M-x org-mode-restart for changes to take effect.

8.6. Note on dimmer.el

The 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:

(use-package dimmer
  :config
  (setq dimmer-fraction 0.3)
  (setq dimmer-adjustment-mode :foreground)
  (setq dimmer-use-colorspace :rgb)

  (dimmer-mode 1))

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 dimmer-fraction has been selected empirically. Users might prefer to tweak it further (increasing it makes the dim effect more pronounced).

Changing the 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.

8.7. Note on display-fill-column-indicator-mode

The 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 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 fill-column-indicator face, as explained elsewhere in this document. For example:

(modus-themes-with-colors
  (custom-set-faces
   `(fill-column-indicator ((,c :foreground ,bg-active)))))

Use theme colors in code with modus-themes-with-colors.

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 :height 1.0 versus :height 1. For example:

(modus-themes-with-colors
  (custom-set-faces
   `(fill-column-indicator ((,c :height 1.0 :background ,bg-inactive :foreground ,bg-inactive)))))

8.8. Note on highlight-parentheses.el

The 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.

Advanced customization.

In the following example, we are assuming that the user wants to (i) re-use color variables provided by the themes, (ii) be able to retain their tweaks while switching between modus-operandi and 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:

(defvar my-highlight-parentheses-use-background t
  "Prefer `highlight-parentheses-background-colors'.")

Then we can update our preference with this:

;; Set to nil to disable backgrounds.
(setq my-highlight-parentheses-use-background nil)

To re-use colors from the themes, we must wrap our code in the modus-themes-with-colors macro. Our implementation must interface with the variables highlight-parentheses-background-colors and/or highlight-parentheses-colors.

So we can have something like this (the doc string of modus-themes-with-colors explains where the names of the colors can be found):

(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 bg-cyan-intense
                                                            bg-magenta-intense
                                                            bg-green-intense
                                                            bg-yellow-intense)
              highlight-parentheses-colors (list cyan
                                                 magenta
                                                 green
                                                 yellow))

      ;; 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)

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 modus-themes-after-load-theme-hook. This is the complete implementation:

;; 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 bg-cyan-intense
                                                            bg-magenta-intense
                                                            bg-green-intense
                                                            bg-yellow-intense)
              highlight-parentheses-colors (list cyan
                                                 magenta
                                                 green
                                                 yellow))

      ;; 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)

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

8.9. Note on mmm-mode.el background colors

The faces used by 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:

  1. Legibility of the text, understood as the contrast ratio between the background and the foreground.
  2. Semantic precision of each face which entails faithfulness to color-coding of the underlying background.

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.

Use theme colors in code with modus-themes-with-colors.

This example uses more vivid background colors, though it comes at the very high cost of degraded legibility.

(modus-themes-with-colors
  (custom-set-faces
   `(mmm-cleanup-submode-face ((,c :background ,bg-yellow-intense)))
   `(mmm-code-submode-face ((,c :background ,bg-inactive)))
   `(mmm-comment-submode-face ((,c :background ,bg-blue-intense)))
   `(mmm-declaration-submode-face ((,c :background ,bg-cyan-intense)))
   `(mmm-default-submode-face ((,c :background ,bg-dim)))
   `(mmm-init-submode-face ((,c :background ,bg-magenta-intense)))
   `(mmm-output-submode-face ((,c :background ,bg-red-intense)))
   `(mmm-special-submode-face ((,c :background ,bg-green-intense)))))

8.10. 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 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 modus-themes-with-colors macro: Use theme colors in code with modus-themes-with-colors.

These are the minimum recommended settings with 16 colors:

(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-cooler
                  magenta-cooler
                  blue
                  magenta-warmer
                  cyan-warmer
                  red-cooler
                  green
                  fg-main
                  cyan
                  yellow
                  blue-warmer
                  red-warmer
                  green-cooler
                  yellow-faint)))

With 8 colors:

(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-cooler
                  cyan-cooler
                  fg-main
                  blue-warmer
                  red-cooler
                  cyan)))

And this is with 4 colors, which produces results that are the closest to the themes’ default aesthetic:

(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-cooler
                  green-warmer)))

If you need to apply desaturation and lightening, you can use what the prism.el documentation recommends, like this (adapting to the examples with the 4, 8, 16 colors):

(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-cooler
                  magenta-cooler
                  magenta)))

8.11. Note on company-mode overlay pop-up

By default, the 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.2, 3

Also consider the corfu package.

8.12. Note on ERC escaped color sequences

The built-in IRC client erc has the ability to colorize any text using escape sequences that start with ^C (inserted with C-q C-c) and are followed by a number for the foreground and background.4 Possible numbers are 0-15, with the first entry being the foreground and the second the background, separated by a comma. Like this ^C1,6. The minimum setup is this:

(add-to-list 'erc-modules 'irccontrols)
(setq erc-interpret-controls-p t
      erc-interpret-mirc-color t)

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:

Modus Operandi
Use foreground color 1 for all backgrounds from 2-15. Like so: C-q C-c1 where N is the background.
Modus Vivendi
Use foreground color 0 for all backgrounds from 2-13. Use foreground 1 for backgrounds 14, 15.

Colors 0 and 1 are white and black respectively. So combine them together, if you must.

8.13. Note on powerline or spaceline

Both Powerline and Spaceline package users will likely need to use the command powerline-reset whenever they make changes to their themes and/or mode line setup.

8.14. Note on SHR colors

Emacs’ HTML rendering library (shr.el) may need explicit configuration to respect the theme’s colors instead of whatever specifications the webpage provides.

Consult the doc string of shr-use-colors.

8.15. Note on SHR fonts

By default, packages that build on top of the Simple HTML Remember (shr) use proportionately spaced fonts. This is controlled by the user option shr-use-fonts, which is set to non-nil by default. To use the standard font instead, set that variable to nil.

Font configurations for Org and others.

Packages affected by this are:

  • elfeed
  • ement
  • eww

This is a non-exhaustive list.

8.16. Note on Ement colors and fonts

The 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 ement-room-prism and can be disabled with:

(setq ement-room-prism nil)

The contrast ratio of these colors is governed by another user option: ement-room-prism-minimum-contrast. By default, it is set to 6 which is slightly below our nominal target. Try this instead:

(setq ement-room-prism-minimum-contrast 7)

With regard to fonts, Ement depends on shr (Note on SHR fonts).

Since we are here, here is an excerpt from Ement’s source code:

(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)

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.

8.17. Note on pdf-tools link hints

Hints are drawn by 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 pdf-links-read-link and the faces it inherits, it needs to be added to your initialization file after you’ve customized any faces.

(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'"))))

8.18. 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:

(setq notmuch-show-logo nil)

8.19. Note on goto-address-mode faces

The built-in 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 notmuch, use this minor-mode automatically.

The faces are not declared with 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:

(setq goto-address-url-face 'link
      goto-address-url-mouse-face 'highlight
      goto-address-mail-face 'link
      goto-address-mail-mouse-face 'highlight)

My personal preference is to set 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 @ character but also because they are often enclosed in angled brackets).

9. Frequently Asked Questions

In this section we provide answers related to some aspects of the Modus themes’ design and application.

9.1. Is the contrast ratio about 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.

9.2. What does it mean to avoid exaggerations?

The Modus themes are designed with restraint, so that their default looks do not overdo it with the application of color.

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.

9.3. Why are colors mostly variants of blue, magenta, cyan?

Due to the innate properties of color, some options are better than others for the accessibility purposes of the themes, the stylistic consistency between modus-operandi and modus-vivendi, and the avoidance of exaggerations in design.

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: #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 #ffffff, which means that all three light channels are fully luminated, while black is #000000 meaning that no light is present (notwithstanding display technology)).

| 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 |

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.

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:

|         | #ffffff |
|---------+---------|
| #990000 |    8.92 |
| #995500 |    5.75 |
| #990099 |    7.46 |

We notice that equal values of red and blue light in #990099 (magenta shade) do not lead to a considerable change in luminance compared with #990000 (red variant). Whereas less amount of green light in #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 manoeuvring 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 modus-vivendi look completely different than modus-operandi, to the effect that the two could not be properly considered part of the same project.

9.4. What is the best setup for legibility?

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.

modus-operandi is best used outdoors or in a room that either gets direct sunlight or has plenty of light. Whereas 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 modus-operandi at night and 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:

xrandr --output LVDS1 --brightness 1.0 --gamma 0.76:0.75:0.68

Typography is another variable. Some font families are blurry at small point sizes. Others may have a regular weight that is lighter (thiner) 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.

9.5. Are these 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 replace the first sixteen escape sequences of a terminal emulator with color values 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.

Again, one must exercise judgement in order to avoid discrimination, where “discrimination” refers to:

  • The treatment of substantially different magnitudes as if they were of the same class.
  • Or the treatment of the same class of magnitudes as if they were of a different class.

(To treat similar things differently; to treat dissimilar things alike.)

If, in other words, one is to enforce uniformity without accounting for the particular requirements of each case—the contextual demands for usability beyond matters of color—they are 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.

9.6. Port the Modus themes to other platforms?

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 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.

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 yellow+blue variants (Overview).

The latter criterion is the “je ne sais quoi” of the artistic aspect of the themes, which is partially fleshed out in this manual.

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 exercize 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.

10. Contributing

This section documents the canonical sources of the themes and the ways in which you can contribute to their ongoing development.

10.1. Sources of the themes

10.2. Issues you can help with

A few tasks you can help with by sending an email to the general modus-themes public mailing list.

  • Suggest refinements to packages that are covered.
  • Report packages not covered thus far.
  • Report bugs, inconsistencies, shortcomings.
  • Help expand the documentation of covered-but-not-styled packages.
  • Suggest refinements to the color palette.
  • Help expand this document or any other piece of documentation.
  • Send patches for code refinements (if you need, ask me for help with Git—we all start out as beginners).

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.

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.

10.3. 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.

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?]

11. Acknowledgements

The Modus themes are a collective effort. Every bit of work matters.

Author/maintainer
Protesilaos Stavrou.
Contributions to code or documentation
Aleksei Gusev, 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, Sergey Nichiporchik, Stephen Gildea, Shreyas Ragavan, Stefan Kangas, Utkarsh Singh, Vincent Murphy, Xinglu Chen, Yuanchen Xie, okamsn.
Ideas and user feedback
Aaron Jensen, Adam Porter, Adam Spiers, Adrian Manea, Aleksei Pirogov, 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, Charlotte Van Petegem, 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, Imran Khan, Iris Garcia, Ivan Popovych, James Ferguson, 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, Laith Bahodi, Len Trigg, Lennart C. Karssen, Luis Miguel Castañeda, Magne Hov, Manuel Giraud, Manuel Uberti, Mark Bestley, Mark Burton, Mark Simpson, Marko Kocic, Markus Beppler, Matt Armstrong, Matthias Fuchs, Mattias Engdegård, 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, Russell Sim, 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, TitusMu, Trey, bepolymathe, bit9tream, bangedorrunt, derek-upham, doolio, fleimgruber, gitrj95, iSeeU, jixiuf, okamsn, pRot0ta1p, soaringbird, tumashu, wakamenod.
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).
Inspiration for certain features
Bozhidar Batsov (zenburn-theme), Fabrice Niessen (leuven-theme).

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.

12. GNU Free Documentation License


                GNU Free Documentation License
                 Version 1.3, 3 November 2008


 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
     
 Everyone is permitted to copy and distribute verbatim copies
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M. Delete any section Entitled "Endorsements".  Such a section
   may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled "Endorsements"
   or to conflict in title with any Invariant Section.
O. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant.  To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version.  Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity.  If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.


5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy.  If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History"
in the various original documents, forming one section Entitled
"History"; likewise combine any sections Entitled "Acknowledgements",
and any sections Entitled "Dedications".  You must delete all sections
Entitled "Endorsements".


6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the rules
of this License for verbatim copying of each of the documents in all
other respects.

You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert a
copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.


7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an "aggregate" if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation's users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which are not themselves
derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half of
the entire aggregate, the Document's Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.


8. TRANSLATION

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections.  You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers.  In case of a disagreement between
the translation and the original version of this License or a notice
or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.


9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense, or distribute it is void, and
will automatically terminate your rights under this License.

However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
fails to notify you of the violation by some reasonable means prior to
60 days after the cessation.

Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does
not give you any rights to use it.


10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the
GNU Free Documentation License from time to time.  Such new versions
will be similar in spirit to the present version, but may differ in
detail to address new problems or concerns.  See
https://www.gnu.org/licenses/.

Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License "or any later version" applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation.  If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.  If the Document
specifies that a proxy can decide which future versions of this
License can be used, that proxy's public statement of acceptance of a
version permanently authorizes you to choose that version for the
Document.

11. RELICENSING

"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works.  A
public wiki that anybody can edit is an example of such a server.  A
"Massive Multiauthor Collaboration" (or "MMC") contained in the site
means any set of copyrightable works thus published on the MMC site.

"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.

"Incorporate" means to publish or republish a Document, in whole or in
part, as part of another Document.

An MMC is "eligible for relicensing" if it is licensed under this
License, and if all works that were first published under this License
somewhere other than this MMC, and subsequently incorporated in whole or
in part into the MMC, (1) had no cover texts or invariant sections, and
(2) were thus incorporated prior to November 1, 2008.

The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009,
provided the MMC is eligible for relicensing.


ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:

    Copyright (c)  YEAR  YOUR NAME.
    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, no Front-Cover Texts, and no Back-Cover Texts.
    A copy of the license is included in the section entitled "GNU
    Free Documentation License".

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the "with...Texts." line with this:

    with the Invariant Sections being LIST THEIR TITLES, with the
    Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.

Footnotes:

1

:height values do not need to be rounded to multiples of ten: the likes of 115 are perfectly valid—some typefaces will change to account for those finer increments.

4

This page explains the basics, though it is not specific to Emacs: https://www.mirc.com/colors.html