Modus Themes (Modus Operandi and Modus Vivendi)

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

The source code of the themes is available on Gitlab, for the time being. A mirror on Github is also on offer. The official manual is after the screenshots.

These are the out-of-the-box looks of modus-operandi and modus-vivendi respectively (click to enlarge the images for more accurate results):

Modus Operandi default

Modus Vivendi default

And those are with some options enabled:

Modus Operandi with basic options

Modus Vivendi with basic options

There are a lot of customization options, so please read the rest of this page.

Official manual

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

The documentation furnished herein corresponds to stable version 1.1.1, released on 2021-01-25. 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 1.2.0-dev. This manual was rebuilt on 2021-02-28 22:13 +0200.

Table of Contents

1 COPYING

Copyright (C) 2020-2021 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 no Front-Cover Texts, and with no Back-Cover Texts.

2 Overview

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

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

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

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

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. There are lots of scenarios on display that draw attention to details and important aspects in the design of the themes. They also showcase the numerous customization options.

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.

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 have updated 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.

Note that older versions of the themes used to be distributed as standalone packages. This practice has been discontinued starting with version 1.0.0 of this project.

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.

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.

4 Enable and load

Before you load a theme, it is necessary to require the main library:

(require 'modus-themes)

Then load the individual theme files with the helper function modus-themes-load-themes:

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

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

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

You may want to make some changes to the available customization options before loading a theme (Customization Options). So this is how a basic setup should look like:

(require 'modus-themes)

;; Your customisations here.  For example:
(setq modus-themes-bold-constructs t
      modus-themes-mode-line '3d)

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

;; Enable the theme of your preference:
(modus-themes-load-operandi)

;; Optionally add a key binding for the toggle between the themes:
(define-key global-map (kbd "<f5>") #'modus-themes-toggle)

Sample configuration for use-package.

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

  1. Those functions call load-theme. Some users prefer to opt for enable-theme instead (Differences between loading and enabling).
  2. The functions will run the modus-themes-after-load-theme-hook as their final step. This can be employed for bespoke configurations (Advanced customization (do-it-yourself)). Experienced users may not wish to rely on such a hook and the functions that run it: they may prefer a custom solution (A theme-agnostic hook for theme loading).

4.1 Sample configuration for use-package

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

(use-package modus-themes
  :ensure
  :init
  ;; Add all your customizations prior to loading the themes
  (setq modus-themes-slanted-constructs t
        modus-themes-bold-constructs nil)

  ;; Load the theme files before enabling a theme (else you get an error).
  (modus-themes-load-themes)
  :config
  ;; Load the theme of your choice:
  (modus-themes-load-operandi) ;; OR (modus-themes-load-vivendi)
  :bind ("<f5>" . modus-themes-toggle))

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.

4.2 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 re-loads) the theme. Whereas the latter simply puts an already loaded theme at the top of the list of enabled items, re-using whatever state was last loaded.

As such, 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 conducts 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)
(require 'modus-operandi-theme)
(require 'modus-vivendi-theme)

(enable-theme 'modus-operandi) ;; OR (enable-theme 'modus-vivendi)

Sample configuration for 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:

Case-by-case face specs using the themes’ palette.

Face specs at scale using the themes’ palette.

5 Customization Options

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

Remember that all customization options must be evaluated before loading a theme (Enable and load).

5.1 Option for more bold constructs

Symbol: modus-themes-bold-constructs

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-line prompts.

5.2 Option for more slanted constructs

Symbol: modus-themes-slanted-constructs

Possible values:

  1. nil (default)
  2. t

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

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

5.3 Option for syntax highlighting

Symbol: modus-themes-syntax

Possible values:

  1. nil (default)
  2. faint
  3. yellow-comments
  4. green-strings
  5. yellow-comments-green-strings
  6. alt-syntax
  7. alt-syntax-yellow-comments
  8. faint-yellow-comments (Part of 1.2.0-dev)

The default style (nil) for code syntax highlighting is a balanced combination of colors on the cyan-blue-magenta side of the spectrum. There is little to no use of greens, yellows, or reds, except when it is necessary.

Option faint is like the default in terms of the choice of palette but applies desaturated color values.

Option yellow-comments adds a yellow tint to comments. The rest of the syntax is the same as the default.

Option green-strings replaces the blue/cyan/cold color variants in strings with greener alternatives. The rest of the syntax remains the same.

Option yellow-comments-green-strings combines yellow comments with green strings and the rest of the default syntax highlighting style.

Option alt-syntax expands the active spectrum by applying color combinations with more contrasting hues between them. Expect to find red and green variants in addition to cyan, blue, magenta.

Option alt-syntax-yellow-comments combines alt-syntax with yellow-comments.

Option faint-yellow-comments combines the faint style with yellow-comments.

5.4 Option for no font mixing

Symbol: modus-themes-no-mixed-fonts

Possible values:

  1. nil (default)
  2. t

By default, the themes configure some spacing-sensitive faces like Org tables and code blocks to always inherit from the fixed-pitch face. This is to ensure that those constructs 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 would appear broken, due to how spacing is done. To disable this behaviour, set the option to t.

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

Font configurations for Org (and others).

5.5 Option for links

Symbol: modus-themes-links

Possible values:

  1. nil (default)
  2. faint
  3. neutral-underline
  4. faint-neutral-underline
  5. no-underline
  6. underline-only
  7. neutral-underline-only (Part of 1.2.0-dev)

The default style (nil) for links is to apply an underline and a saturated color to the affected text. The color of the two is the same, which makes the link fairly prominent.

Option faint follows the same approach as the default, but uses less intense colors.

Option neutral-underline changes the underline’s color to a subtle gray, while retaining the default text color.

Option faint-neutral-underline combines a desaturated text color with a subtle gray underline.

Option no-underline removes link underlines altogether, while retaining their original fairly vivid color.

Option underline-only applies a prominent underline while making the affected text colorless (it uses the same foreground as the theme’s default).

Option neutral-underline-only makes the text colorless while using a subtle gray underline below it.

NOTE: The placement of the underline, i.e. its proximity to the affected text, is controlled by the built-in x-underline-at-descent-line, x-use-underline-position-properties, underline-minimum-offset. Please refer to their documentation strings.

5.6 Option for command prompt styles

Symbol: modus-themes-prompts

Possible values:

  1. nil (default)
  2. subtle-accented (subtle remains for backward compatibility)
  3. intense-accented (intense remains for backward compatibility)
  4. subtle-gray
  5. intense-gray

The default does not use any background for minibuffer and command line prompts. It relies exclusively on an accented foreground color.

Options subtle-accented and intense-accented will change both the background and the foreground values to use accented color combinations that follow the hue of the default styles’ foreground (e.g. the default minibuffer prompt is cyan text, so these combinations will involved a cyan background and an appropriate cyan foreground). The difference between the two is that the latter has a more pronounced/noticeable effect than the former.

Options subtle-gray, intense-gray are like their accented counterparts, except they use grayscale values.

5.7 Option for mode line presentation

Symbol: modus-themes-mode-line

Possible values:

  1. nil (default)
  2. 3d
  3. moody
  4. borderless
  5. borderless-3d
  6. borderless-moody

The default produces a two-dimensional effect both for the active and inactive modelines. The differences between the two are limited to distinct shades of grayscale values, with the active being more intense than the inactive.

Option 3d will make the active modeline look like a three-dimensional rectangle. Inactive modelines remain 2D, though they are slightly toned down relative to the default. This aesthetic is virtually the same as what you get when you run Emacs without any customizations (emacs -Q on the command line).

While moody removes all box effects from the modelines and applies underline and overline properties instead. It also tones down a bit the inactive modelines. This is meant to optimize things for use with the moody package (hereinafter referred to as “Moody”), though it can work fine even without it.

The borderless option uses the same colors as the default (nil value), but removes the border effect. This is done by making the box property use the same color as the background, effectively blending the two and creating some padding.

The borderless-3d and borderless-moody approximate the 3d and moody options respectively, while removing the borders. However, to ensure that the inactive modelines remain visible, they apply a slightly more prominent background to them than what their counterparts do (same inactive background as with the default).

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

Furthermore, because Moody expects an underline and overline instead of a box style, it is advised you include this in your setup:

(setq x-underline-at-descent-line t)

5.8 Option for completion framework aesthetics

Symbol: modus-themes-completions

Possible values:

  1. nil (default)
  2. moderate
  3. opinionated

This is a special option that has different effects depending on the completion UI. The interfaces can be grouped in two categories, based on their default aesthetics: (i) those that only or mostly use foreground colors for their interaction model, and (ii) those that combine background and foreground values for some of their metaphors. The former category encompasses Icomplete, Ido, Selectrum as well as pattern matching styles like Orderless and Flx. The latter covers Helm, Ivy, and similar.

A value of nil will respect the metaphors of each completion framework.

Option moderate applies a combination of background and foreground that is fairly subtle. For Icomplete and friends this constitutes a departure from their default aesthetics, however the difference is small. While Helm, Ivy et al appear slightly different than their original looks, as they are toned down a bit.

Option opinionated uses color combinations that refashion the completion UI. For the Icomplete camp this means that intense background and foreground combinations are used: in effect their looks emulate those of Helm, Ivy and co. in their original style. Whereas the other group of packages will revert to an even more nuanced aesthetic with some additional changes to the choice of hues.

To appreciate the scope of this customization option, you should spend some time with every one of the nil (default), moderate, and opinionated possibilities.

5.9 Option for fringe visibility

Symbol: modus-themes-fringes

Possible values:

  1. nil (default)
  2. subtle
  3. intense

The default is to use the same color as that of the main background, meaning that the fringes are not obvious though they still occupy the space given to them by fringe-mode.

Options subtle and intense apply a gray background, making the fringes visible. The difference between the two is one of degree, as their names imply.

5.10 Option for language checkers

Symbol: modus-themes-lang-checkers

Possible values:

  1. nil (default)
  2. subtle-foreground
  3. intense-foreground
  4. straight-underline
  5. subtle-foreground-straight-underline
  6. intense-foreground-straight-underline
  7. colored-background

Nil (the default) applies a color-coded underline to the affected text, while it leaves the original foreground in tact. If the display spec where Emacs runs in has support for it (e.g. Emacs GUI), the underline’s style is that of a wave, otherwise it is a straight line.

Options subtle-foreground and intense-foreground follow the same color-coding pattern and wavy underline of the default, while extending it with a corresponding foreground value for the affected text. The difference between the two options is one of degree, as their names suggest.

Option straight-underline is like the default but always applies a straight line under the affected text. Same principle for subtle-foreground-straight-underline and its counterpart intense-foreground-straight-underline.

Option colored-background uses a straight underline, a tinted background, and a suitable foreground. All are color-coded. This is the most intense combination of face properties.

The present variable affects packages and/or face groups such as those of flyspell, flymake, flycheck, artbollocks-mode, and writegood-mode.

NOTE: The placement of the straight underline, though not the wave style, is controlled by the built-in x-underline-at-descent-line, x-use-underline-position-properties, underline-minimum-offset. Please refer to their documentation strings.

5.11 Option for line highlighting (hl-line-mode)

Symbol: modus-themes-intense-hl-line

Possible values:

  1. nil (default)
  2. t

The default is to use a subtle gray background for hl-line-mode and its global equivalent.

With a non-nil value (t) use a more prominent background color instead.

This affects several packages that enable hl-line-mode, such as elfeed and mu4e.

5.12 Option for line numbers (display-line-numbers-mode)

(Part of 1.2.0-dev)

Symbol: modus-themes-subtle-line-numbers

Possible value:

  1. nil (default)
  2. t

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

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

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

5.13 Option for parenthesis matching (show-paren-mode)

Symbol: modus-themes-paren-match

Possible values:

  1. nil (default)
  2. subtle-bold
  3. intense
  4. intense-bold

Nil means to use a subtle tinted background color for the matching delimiters.

Option intense applies a saturated background color.

Option subtle-bold is the same as the default, but also makes use of bold typographic weight (inherits the bold face).

Option intense-bold is the same as intense, while it also uses a bold weight.

This customization variable affects tools such as the built-in show-paren-mode and the smartparens package.

5.14 Option for active region

Symbol: modus-themes-region

Possible values:

  1. nil (default)
  2. no-extend
  3. bg-only
  4. bg-only-no-extend

Nil means to only use a prominent gray background with a neutral foreground. The foreground overrides all syntax highlighting. The region extends to the edge of the window.

Option no-extend preserves the default aesthetic but prevents the region from extending to the edge of the window.

Option bg-only applies a faint tinted background that is distinct from all others used in the theme, while it does not override any existing colors. It extends to the edge of the window.

Option bg-only-no-extend is a combination of the bg-only and no-extend options.

5.15 Option for diff buffer looks

Symbol: modus-themes-diffs

Possible values:

  1. nil (default)
  2. desaturated
  3. fg-only
  4. bg-only
  5. deuteranopia (Part of 1.2.0-dev)

By default the themes apply rich coloration to the output of diffs, such as those of diff-mode, ediff, smerge-mode, and Magit. These are color combinations of an accented background and foreground so that, for example, added lines have a pronounced green background with an appropriate shade of green for the affected text. Word-wise or “refined” changes follow this pattern but use different shades of those colors to remain distinct.

Option desaturated tones down all relevant color values. It still combines an accented background with an appropriate foreground, yet its overall impression is fairly subtle. Refined changes are a bit more intense to fulfil their intended function, though still less saturated than default.

Option fg-only will remove most accented backgrounds and instead rely on color-coded text to denote changes. For instance, added lines use a green foreground, while their background is the same as the rest of the buffer. Word-wise highlights still use a background value which is, nonetheless, more subtle than its default equivalent.

Option bg-only applies color-coded backgrounds but does not override any syntax highlighting that may be present. This makes it suitable for use with a non-nil value for diff-font-lock-syntax (which is the default for diff-mode buffers in Emacs 27 or higher).

Option deuteranopia optimizes for red-green color deficiency. It replaces all instances of green with blue variants. This is to ensure that indicators for “removed” and “added” states are not mistaken for each other.

Concerning Magit, an extra set of tweaks are introduced for the effect of highlighting the current diff hunk, so as to remain aligned with the overall experience of that mode. Expect changes that are consistent with the overall intent of the aforementioned. Note, however, that the bg-only option will not deliver the intended results in Magit diffs because no syntax highlighting is used there (last checked with Magit version 20201116.1057, though upstream has a plan to eventually support such a feature—this entry shall be updated accordingly).

5.16 Option for org-mode block styles

Symbol: modus-themes-org-blocks

Possible values:

  1. nil (default)
  2. grayscale
  3. rainbow

The default is to use the same background as the rest of the buffer for the contents of the block.

Option grayscale applies a subtle neutral gray background to the block’s contents. It will also extend to the edge of the window the background of the “begin” and “end” block delimiter lines (only relevant for Emacs versions >= 27 where the ’extend’ keyword is part of the face specifications).

Option rainbow uses an accented background for the contents of the block. The exact color will depend on the programming language and is controlled by the org-src-block-faces variable. This is most suitable for users who work on literate programming documents that mix and match several languages.

Note that the “rainbow” blocks may require you to also reload the major-mode so that the colors are applied consistently throughout: use M-x org-mode or M-x org-mode-restart to refresh the buffer. Or start typing in each code block (inefficient at scale, but it still works).

5.17 Option for org-habit graph styles

Symbol: modus-themes-org-habit

Possible values:

  1. nil (default)
  2. simplified
  3. traffic-light

The default is meant to conform with the original aesthetic of org-habit. It employs all four color codes that correspond to the org-habit states—clear, ready, alert, and overdue—while distinguishing between their present and future variants. This results in a total of eight colors in use: red, yellow, green, blue, in tinted and shaded versions. They cover the full set of information provided by the org-habit consistency graph.

Option simplified is like the default except that it removes the dichotomy between current and future variants by applying uniform color-coded values. It applies a total of four colors: red, yellow, green, blue. They produce a simplified consistency graph that is more legible (or less “busy”) than the default. The intent is to shift focus towards the distinction between the four states of a habit task, rather than each state’s present/future outlook.

Option traffic-light further reduces the available colors to red, yellow, and green. As in simplified, present and future variants appear uniformly, but differently from it, the ’clear’ state is rendered in a green hue, instead of the original blue. This is meant to capture the use-case where a habit task being “too early” is less important than it being “too late”. The difference between ready and clear states is attenuated by painting both of them using shades of green. This option thus highlights the alert and overdue states.

5.18 Option for the headings' overall style

This is defined as an alist and, therefore, uses a different approach than other customization options documented in this manual.

Symbol: modus-themes-headings

Possible values, which can be specified for each heading level (examples further below):

  • nil (default fallback option—covers all heading levels)
  • t (default style for a single heading, when the fallback differs)
  • no-bold
  • line
  • line-no-bold
  • rainbow
  • rainbow-line
  • rainbow-line-no-bold
  • highlight
  • highlight-no-bold
  • rainbow-highlight
  • rainbow-highlight-no-bold
  • section
  • section-no-bold
  • rainbow-section
  • rainbow-section-no-bold
  • no-color
  • no-color-no-bold

To control faces per level from 1-8, use something like this:

(setq modus-themes-headings
      '((1 . section)
        (2 . section-no-bold)
        (3 . rainbow-line)
        (t . rainbow-line-no-bold)))

The above uses the section value for heading levels 1, section-no-bold for headings 2, rainbow-line for 3. All other levels fall back to rainbow-line-no-bold.

To set a uniform value for all heading levels, use this pattern:

;; A given style for every heading
(setq modus-themes-headings
      '((t . section)))

;; Default aesthetic for every heading
(setq modus-themes-headings
      '())

The default style for headings uses a fairly desaturated foreground value in combination with bold typographic weight. To specify this style for a given level N, assuming you wish to have another fallback option, just specify the value t like this:

(setq modus-themes-headings
      '((1 . t)
        (2 . line)
        (t . rainbow-line-no-bold)))

A description of all other possible styles beyond the default:

  • no-bold retains the default text color while removing the bold typographic weight.
  • line is the same as the default plus an overline across the heading’s length.
  • line-no-bold is the same as line without bold weight.
  • rainbow uses a more colorful foreground in combination with bold typographic weight.
  • rainbow-line is the same as rainbow plus an overline.
  • rainbow-line-no-bold is the same as rainbow-line without the bold weight.
  • highlight retains the default style of a fairly desaturated foreground combined with a bold weight and adds to it a subtle accented background.
  • highlight-no-bold is the same as highlight without a bold weight.
  • rainbow-highlight is the same as highlight but with a more colorful foreground.
  • rainbow-highlight-no-bold is the same as rainbow-highlight without a bold weight.
  • section retains the default looks and adds to them both an overline and a slightly accented background. It is, in effect, a combination of the line and highlight values.
  • section-no-bold is the same as section without a bold weight.
  • rainbow-section is the same as section but with a more colorful foreground.
  • rainbow-section-no-bold is the same as rainbow-section without a bold weight.
  • no-color does not apply any color to the heading, meaning that it uses the foreground of the default face. It still renders the text with a bold typographic weight.
  • no-color-no-bold is like no-color but without the bold weight.

5.19 Option for scaled headings

Symbol: modus-themes-scale-headings

Possible values:

  1. nil (default)
  2. t

The default is to use the same size for headings and paragraph text.

With a non-nil value (t) make headings larger in height relative to the main text. This is noticeable in modes like Org, Markdown, and Info.

5.19.1 Control the scale of headings

In addition to the toggle for enabling scaled headings, users can also specify a number of their own.

  • If it is a floating point, say, 1.5, it is interpreted as a multiple of the base font size. This is the recommended method, because it will always adapt to changes in the base font size, such as while using the text-scale-adjust command.
  • If it is an integer, it is read as an absolute font height that is 1/10 of the typographic point size. Thus a value of 18pt must be expressed as 180. Setting an absolute value is discouraged, as it will break the layout in cases where the base font size must change, such as with the text-scale-adjust command (Font configurations). While we discourage using absolute values, we still provide for this option for users who do not need to perform text-scaling operations or who are content with whatever discrepancies in height.

Below are the variables in their default values, using the floating point paradigm. The numbers are very conservative, but one is free to change them to their liking, such as 1.2, 1.4, 1.6, 1.8, 2.0—or use a resource for finding a consistent scale:

(setq modus-themes-scale-1 1.05
      modus-themes-scale-2 1.1
      modus-themes-scale-3 1.15
      modus-themes-scale-4 1.2
      modus-themes-scale-5 1.3)

As for the application of that scale, the variables that range from modus-themes-scale-1 up to modus-themes-scale-4 apply to regular headings within the context of the given major mode. The former is the smallest, while the latter is the largest. “Regular headings” are those that have a standard syntax for their scale, such as Org mode’s eight levels of asterisks or Markdown’s six columns.

Whereas modus-themes-scale-5 is applied to special headings that do not conform with the aforementioned syntax, yet which are expected to be larger than the largest value on that implied scale. Put concretely, Org’s #+title meta datum is not part of the eight levels of headings in an Org file, yet is supposed to signify the primary header. Similarly, the Org Agenda’s structure headings are not part of a recognisable scale and so they also get modus-themes-scale-5.

Users who wish to maintain scaled headings for the normal syntax while preventing special headings from standing out, can assign a value of 1.0 to modus-themes-scale-5 to make it the same as body text (or whatever value would render it indistinguishable from the desired point of reference).

Note that in earlier versions of Org, scaling would only increase the size of the heading, but not of keywords that were added to it, like “TODO”. The issue has been fixed upstream: https://protesilaos.com/codelog/2020-09-24-org-headings-adapt/.

5.20 Option for variable-pitch font in UI elements

Symbol: modus-themes-variable-pitch-ui

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.

5.21 Option for variable-pitch font in headings

Symbol: modus-themes-variable-pitch-headings

Possible values:

  1. nil (default)
  2. t

The default is to use the main font family, which typically is monospaced.

With a non-nil value (t) apply a proportionately spaced typeface, else “variable-pitch”, to headings (such as in Org mode).

Font configurations for Org and others.

6 Advanced customization (do-it-yourself)

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 labelled as “do-it-yourself” or “DIY”.

6.1 Per-theme customization settings (DIY)

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-operandi))

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

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

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.

6.2 Case-by-case face specs using the themes’ palette (DIY)

This section is about tweaking individual faces. If you plan to do things at scale, consult the next section: Set multiple faces.

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

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

(modus-themes-color 'blue)

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

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

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

Do C-h v on the aforementioned variables to check all the available symbols that can be passed to this function.

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

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

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

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

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

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

A theme-agnostic hook for theme loading.

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

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

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

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

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

Take the previous example with the cursor face:

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

6.3 Face specs at scale using the themes’ palette (DIY)

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

The modus-themes-with-colors macro lets you retrieve multiple color values by employing the backquote/backtick and comma notation. The values are stored in the alists modus-themes-operandi-colors and modus-themes-vivendi-colors, while the macro always queries that of the active Modus theme.

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

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

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

This is how it works:

(modus-themes-with-colors
    (custom-set-faces
     `(cursor ((,class :background ,blue)))
     `(mode-line ((,class :inherit variable-pitch
                          :background ,yellow-nuanced-bg
                          :foreground ,yellow-nuanced-fg)))
     `(mode-line-inactive ((,class :inherit variable-pitch
                                   :background ,blue-nuanced-bg
                                   :foreground ,blue-nuanced-fg)))
     `(line-number ((,class :background unspecified :foreground ,fg-unfocused)))
     `(line-number-current-line ((,class :background unspecified
                                         :foreground ,red-alt-other)))))

We are showing some uses of :inherit and of the special unspecified value so that you can appreciate how a theme can be written. Otherwise you can identify the color variables by the comma prefixed to them.

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

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

(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(cursor ((,class :background ,blue)))
     `(mode-line ((,class :inherit variable-pitch
                          :background ,yellow-nuanced-bg
                          :foreground ,yellow-nuanced-fg)))
     `(mode-line-inactive ((,class :inherit variable-pitch
                                   :background ,blue-nuanced-bg
                                   :foreground ,blue-nuanced-fg)))
     `(line-number ((,class :background unspecified :foreground ,fg-unfocused)))
     `(line-number-current-line ((,class :background unspecified
                                         :foreground ,red-alt-other))))))

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

A theme-agnostic hook for theme loading.

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

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

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

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

A complete example with some more opinionated stylistic choices:

(defun my-modus-themes-custom-faces ()
  (modus-themes-with-colors
    (custom-set-faces
     `(cursor ((,class :background ,(modus-themes-color-alts 'blue 'green))))
     `(header-line ((,class :inherit variable-pitch)))
     `(tab-bar ((,class :inherit variable-pitch)))
     `(mode-line
       ((,class :inherit variable-pitch
                :box ,(modus-themes-color-alts 'yellow-subtle-bg 'magenta-subtle-bg)
                :background ,(modus-themes-color-alts 'yellow-nuanced-bg 'magenta-nuanced-bg)
                :foreground ,(modus-themes-color-alts 'yellow-nuanced-fg 'magenta-nuanced-fg))))
     `(mode-line-inactive ((,class :inherit variable-pitch)))
     `(line-number ((,class :background unspecified :foreground ,fg-unfocused)))
     `(line-number-current-line
       ((,class :background ,(modus-themes-color-alts 'yellow-nuanced-bg 'magenta-nuanced-bg)
                :foreground ,(modus-themes-color-alts 'red-alt 'magenta-alt-other)))))))

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

6.4 Override colors (DIY)

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

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

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

As you can see, we bind a key to a hexadecimal RGB color value. Now say you wish to override those specific values and have your changes propagate to all faces that use those keys. You could write something like this, which adds a subtle ochre tint:

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

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

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

(setq modus-themes-operandi-color-overrides nil)

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

(define-minor-mode my-modus-themes-tinted
  "Tweak some Modus themes colors."
  :init-value nil
  :global t
  (if my-modus-themes-tinted
      (setq modus-themes-operandi-color-overrides
            '((bg-main . "#fefcf4")
              (bg-dim . "#faf6ef")
              (bg-alt . "#f7efe5")
              (bg-hl-line . "#f4f0e3")
              (bg-active . "#e8dfd1")
              (bg-inactive . "#f6ece5")
              (bg-region . "#c6bab1")
              (bg-header . "#ede3e0")
              (bg-tab-bar . "#dcd3d3")
              (bg-tab-active . "#fdf6eb")
              (bg-tab-inactive . "#c8bab8")
              (fg-unfocused . "#55556f"))
            modus-themes-vivendi-color-overrides
            '((bg-main . "#100b17")
              (bg-dim . "#161129")
              (bg-alt . "#181732")
              (bg-hl-line . "#191628")
              (bg-active . "#282e46")
              (bg-inactive . "#1a1e39")
              (bg-region . "#393a53")
              (bg-header . "#202037")
              (bg-tab-bar . "#262b41")
              (bg-tab-active . "#120f18")
              (bg-tab-inactive . "#3a3a5a")
              (fg-unfocused . "#9a9aab")))
    (setq modus-themes-operandi-color-overrides nil
          modus-themes-vivendi-color-overrides nil)))

With this in place, one can invoke M-x my-modus-themes-tinted and then load the Modus theme of their choice. The new colors will come into effect. Switching between the themes will also use the overrides.

Given that this is a user-level customisation, one is free to implement whatever color values they desire, even if the possible combinations fall below the minimum 7:1 contrast ratio that governs the design of the themes (the WCAG AAA legibility standard). Preferences aside, it is advised to inspect the source code of modus-themes-operandi-colors and modus-themes-vivendi-colors to read the inline commentary: it explains what the intended use of each subset is.

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

6.5 Font configurations for Org and others (DIY)

The themes are designed to cope well with mixed font configurations.

Option for no font mixing.

This mostly concerns org-mode and markdown-mode, though expect to find it elsewhere like in Info-mode.

In practice it means that the user can safely opt for a more prose-friendly proportionately spaced typeface as their default, while letting 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.

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 1.0)

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 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).

6.6 Custom Org user faces (DIY)

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:

(setq org-todo-keyword-faces
      '(("MEET" . '(font-lock-preprocessor-face org-todo))
        ("STUDY" . '(font-lock-variable-name-face org-todo))
        ("WRITE" . '(font-lock-type-face 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 important: the last item is applied over the previous ones. 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 . '(org-scheduled-today 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.

Custom face specs using the themes’ palette.

Check color combinations.

6.7 Measure color contrast (DIY)

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 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 override some of the themes’ colors: Override colors.

6.8 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
  :after solar
  (setq circadian-themes '((:sunrise . modus-operandi)
                           (:sunset  . modus-vivendi)))
  (circadian-setup))

6.9 A theme-agnostic hook for theme loading (DIY)

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

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

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

A theme-agnostic setup can be configured thus:

(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.

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

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
  • ag
  • alert
  • all-the-icons
  • annotate
  • anzu
  • apropos
  • apt-sources-list
  • artbollocks-mode
  • auctex and TeX
  • auto-dim-other-buffers
  • avy
  • awesome-tray
  • bbdb
  • binder
  • bm
  • bongo
  • boon
  • breakpoint (provided by the built-in gdb-mi.el library)
  • buffer-expose
  • calendar and diary
  • calfw
  • centaur-tabs
  • cfrs
  • change-log and log-view (such as vc-print-log, vc-print-root-log)
  • cider
  • circe
  • color-rg
  • column-enforce-mode
  • company-mode*
  • company-posframe
  • compilation-mode
  • completions
  • consult
  • counsel*
  • counsel-css
  • counsel-notmuch
  • counsel-org-capture-string
  • cov
  • cperl-mode
  • csv-mode
  • ctrlf
  • custom (what you get with M-x customize)
  • dap-mode
  • dashboard (emacs-dashboard)
  • deadgrep
  • debbugs
  • define-word
  • deft
  • dictionary
  • diff-hl
  • diff-mode
  • dim-autoload
  • dir-treeview
  • dired
  • dired-async
  • dired-git
  • dired-git-info
  • dired-narrow
  • dired-subtree
  • diredc
  • diredfl
  • diredp (dired+)
  • disk-usage
  • display-fill-column-indicator-mode
  • doom-modeline
  • dynamic-ruler
  • easy-jekyll
  • easy-kill
  • ebdb
  • ediff
  • eglot
  • el-search
  • eldoc-box
  • elfeed
  • elfeed-score
  • emms
  • enhanced-ruby-mode
  • epa
  • equake
  • erc
  • eros
  • ert
  • eshell
  • eshell-fringe-status
  • eshell-git-prompt
  • eshell-prompt-extras (epe)
  • eshell-syntax-highlighting
  • evil* (evil-mode)
  • evil-goggles
  • evil-snipe
  • evil-visual-mark-mode
  • eww
  • exwm
  • eyebrowse
  • fancy-dabbrev
  • flycheck
  • flycheck-color-mode-line
  • flycheck-indicator
  • flycheck-posframe
  • flymake
  • flyspell
  • flyspell-correct
  • flx
  • freeze-it
  • frog-menu
  • focus
  • fold-this
  • font-lock (generic syntax highlighting)
  • forge
  • fountain (fountain-mode)
  • geiser
  • git-commit
  • git-gutter (and variants)
  • git-lens
  • git-rebase
  • git-timemachine
  • git-walktree
  • gnus
  • golden-ratio-scroll-screen
  • helm*
  • helm-ls-git
  • helm-switch-shell
  • helm-xref
  • helpful
  • highlight-blocks
  • highlight-defined
  • highlight-escape-sequences (hes-mode)
  • highlight-indentation
  • highlight-numbers
  • highlight-symbol
  • highlight-tail
  • highlight-thing
  • hl-defined
  • hl-fill-column
  • hl-line-mode
  • hl-todo
  • hydra
  • hyperlist
  • ibuffer
  • icomplete
  • icomplete-vertical
  • ido-mode
  • iedit
  • iflipb
  • imenu-list
  • indium
  • info
  • info-colors
  • interaction-log
  • ioccur
  • isearch, occur, etc.
  • isl (isearch-light)
  • ivy*
  • ivy-posframe
  • jira (org-jira)
  • journalctl-mode
  • js2-mode
  • julia
  • jupyter
  • kaocha-runner
  • keycast
  • line numbers (display-line-numbers-mode and global variant)
  • lsp-mode
  • lsp-ui
  • macrostep
  • magit
  • magit-imerge
  • make-mode
  • man
  • marginalia
  • markdown-mode
  • markup-faces (adoc-mode)
  • mentor
  • messages
  • minibuffer-line
  • minimap
  • mmm-mode (Part of 1.2.0-dev)
  • modeline
  • mood-line
  • moody
  • mpdel
  • mu4e
  • mu4e-conversation
  • multiple-cursors
  • neotree
  • no-emoji
  • notmuch
  • num3-mode
  • nxml-mode
  • objed
  • orderless
  • org*
  • org-journal
  • org-noter
  • org-pomodoro
  • org-recur
  • org-roam
  • org-superstar
  • org-table-sticky-header
  • org-tree-slide
  • org-treescope
  • origami
  • outline-mode
  • outline-minor-faces
  • package (what you get with M-x list-packages)
  • page-break-lines
  • paradox
  • paren-face
  • parrot
  • pass
  • pdf-tools
  • persp-mode
  • perspective
  • phi-grep
  • phi-search
  • pkgbuild-mode
  • pomidor
  • popup
  • powerline
  • powerline-evil
  • prism (Note for prism.el)
  • proced
  • prodigy
  • quick-peek (Part of 1.2.0-dev)
  • racket-mode
  • rainbow-blocks
  • rainbow-identifiers
  • rainbow-delimiters
  • rcirc
  • recursion-indicator
  • regexp-builder (also known as re-builder)
  • rg (rg.el)
  • ripgrep
  • rmail
  • ruler-mode
  • sallet
  • selectrum
  • selectrum-prescient (Part of 1.2.0-dev)
  • semantic
  • sesman
  • shell-script-mode
  • shortdoc (Part of 1.2.0-dev)
  • show-paren-mode
  • shr
  • side-notes
  • sieve-mode
  • skewer-mode
  • smart-mode-line
  • smartparens
  • smerge
  • solaire
  • spaceline
  • speedbar
  • spell-fu
  • stripes
  • suggest
  • switch-window
  • swiper
  • swoop
  • sx
  • symbol-overlay
  • syslog-mode
  • table (built-in table.el)
  • telephone-line
  • terraform-mode
  • term
  • tomatinho
  • transient (pop-up windows such as Magit’s)
  • trashed
  • treemacs
  • tty-menu
  • tuareg
  • typescript
  • undo-tree
  • vc (built-in mode line status for version control)
  • vc-annotate (the out put of C-x v g)
  • vdiff
  • vimish-fold
  • visible-mark
  • visual-regexp
  • volatile-highlights
  • vterm
  • wcheck-mode
  • web-mode
  • wgrep
  • which-function-mode
  • which-key
  • whitespace-mode
  • window-divider-mode
  • winum
  • writegood-mode
  • woman
  • xah-elisp-mode
  • xref
  • xterm-color (and ansi-colors)
  • yaml-mode
  • yasnippet
  • ztree

Plus many other miscellaneous faces that are provided by the upstream GNU Emacs distribution.

7.2 Indirectly covered packages

These do not require any extra styles because they are configured to inherit from some basic faces. Please confirm.

  • edit-indirect
  • evil-owl
  • fortran-mode
  • goggles
  • i3wm-config-mode
  • perl-mode
  • php-mode
  • rjsx-mode
  • swift-mode
  • tab-bar-echo-area

8 Notes for individual packages

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

8.1 Note for display-fill-column-indicator-mode

While designing the style for display-fill-column-indicator-mode, we stayed close to the mode’s defaults: to apply a subtle foreground color to the fill-column-indicator face, which blends well with the rest of theme and is consistent with the role of that mode. This is to not upset the expectations of users.

Nevertheless, display-fill-column-indicator-mode has some known limitations pertaining to its choice of using typographic characters to draw its indicator. What should be a continuous vertical line might appear as a series of dashes in certain contexts or under specific conditions: a non-default value for line-spacing, scaled and/or variable-pitch headings have been observed to cause this effect.

Given that we cannot control such factors, it may be better for affected users to deviate from the default style of the fill-column-indicator face. Instead of setting a foreground color, one could use a background and have the foreground be indistinguishable from it. For example:

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

Face specs at scale using the themes’ palette.

8.2 Note for 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.

Face specs at scale using the themes’ palette.

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

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

8.3 Note for 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 customisations, 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: Face specs at scale using the themes’ palette.

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-alt-other
                  magenta-alt-other
                  blue
                  magenta-alt
                  cyan-alt
                  red-alt-other
                  green
                  fg-main
                  cyan
                  yellow
                  blue-alt
                  red-alt
                  green-alt-other
                  fg-special-warm)))

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 fg-special-cold
                  magenta
                  magenta-alt-other
                  cyan-alt-other
                  fg-main
                  blue-alt
                  red-alt-other
                  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 fg-main
                  cyan-alt-other
                  magenta-alt-other
                  magenta)))

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-alt-other
                  magenta-alt-other
                  magenta)))

8.4 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

8.5 Note for ERC escaped color sequences

The built-in IRC client erc has the ability to colorise 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.

8.6 Note for 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 modeline setup.

8.7 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 C-h v shr-use-colors.

8.8 Note for Helm grep

There is one face from the Helm package that is meant to highlight the matches of a grep or grep-like command (ag or ripgrep). It is helm-grep-match. However, this face can only apply when the user does not pass --color=always as a command-line option for their command.

Here is the docstring for that face, which is defined in the helm-grep.el library (you can visit the source code with M-x find-library).

Face used to highlight grep matches. Have no effect when grep backend use “–color=”

The user must either remove --color from the flags passed to the grep function, or explicitly use --color=never (or equivalent). Helm provides user-facing customization options for controlling the grep function’s parameters, such as helm-grep-default-command and helm-grep-git-grep-command.

When --color=always is in effect, the grep output will use red text in bold letter forms to present the matching part in the list of candidates. That style still meets the contrast ratio target of >= 7:1 (accessibility standard WCAG AAA), because it draws the reference to ANSI color number 1 (red) from the already-supported array of ansi-color-names-vector.

8.9 Note on vc-annotate-background-mode

Due to the unique way vc-annotate (C-x v g) applies colors, support for its background mode (vc-annotate-background-mode) is disabled at the theme level.

Normally, such a drastic measure should not belong in a theme: assuming the user’s preferences is bad practice. However, it has been deemed necessary in the interest of preserving color contrast accessibility while still supporting a useful built-in tool.

If there actually is a way to avoid such a course of action, without prejudice to the accessibility standard of this project, then please report as much or send patches (Contributing).

8.10 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'"))))

9 Contributing

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

9.1 Sources of the themes

The modus-operandi and modus-vivendi themes are built into Emacs. Currently they are in Emacs’ git main branch (trunk), which is tracking the next development release target.

The source code of the themes is available on Gitlab, for the time being. A mirror on Github is also on offer.

An HTML version of this manual is provided as an extension of the author’s personal website (does not rely on any non-free code).

9.2 Issues you can help with

A few tasks you can help with:

  • 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.
  • Merge requests for code refinements.

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.

9.3 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?]

10 Acknowledgements

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

Author/maintainer
Protesilaos Stavrou.
Contributions to code or documentation
Anders Johansson, Basil L. Contovounesios, Carlo Zancanaro, Eli Zaretskii, Kostadin Ninev, Madhavan Krishnan, Markus Beppler, Matthew Stevenson, Nicolas De Jaeghere, Shreyas Ragavan, Stefan Kangas, Vincent Murphy, Xinglu Chen.
Ideas and user feedback
Aaron Jensen, Adam Spiers, Adrian Manea, Alex Griffin, Alex Peitsinis, Alexey Shmalko, Alok Singh, Anders Johansson, André Alexandre Gomes, Arif Rezai, Basil L. Contovounesios, Burgess Chang, Christian Tietze, Christopher Dimech, Damien Cassou, Daniel Mendler, Dario Gjorgjevski, David Edmondson, Davor Rotim, Divan Santana, Gerry Agbobada, Gianluca Recchia, Gustavo Barros, Hörmetjan Yiltiz, Ilja Kocken, Iris Garcia, Jeremy Friesen, John Haman, Kevin Fleming, Kostadin Ninev, Len Trigg, Manuel Uberti, Mark Burton, Markus Beppler, Michael Goldenberg, Morgan Smith, Murilo Pereira, Nicolas De Jaeghere, Paul Poloskov, Pete Kazmier, Peter Wu, Philip K., Pierre Téchoueyres, Roman Rudakov, Ryan Phillips, Shreyas Ragavan, Simon Pugnet, Tassilo Horn, Thibaut Verron, Trey Merkley, Togan Muftuoglu, Toon Claes, Uri Sharf, Utkarsh Singh, Vincent Foley. As well as users: Ben, CsBigDataHub1, Emacs Contrib, Eugene, Fourchaux, Fredrik, Moesasji, Nick, TheBlob42, bepolymathe, doolio, fleimgruber, iSeeU, jixiuf, okamsn, tycho garen.
Packaging
André Alexandre Gomes, Dimakakos Dimos, Morgan Smith, Nicolas Goaziou (Guix), Dhavan Vaidya (Debian), Stefan Kangas (core Emacs), Stefan Monnier (GNU Elpa).
Inspiration for certain features
Bozhidar Batsov (zenburn-theme), Fabrice Niessen (leuven-theme).

Special thanks, in no particular order, to Manuel Uberti and Omar Antolín Camarena for their long time contributions and insightful commentary.

11 Meta

If you are curious about the principles that govern the development of this project read the essay On the design of the Modus themes (2020-03-17).

Here are some more publications for those interested in the kind of work that goes into this project (sometimes the commits also include details of this sort):

And here are the canonical sources of this project’s documentation:

Manual
https://protesilaos.com/modus-themes
Change Log
https://protesilaos.com/modus-themes-changelog
Screenshots
https://protesilaos.com/modus-themes-pictures

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.
     <https://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.

This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.  It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does.  But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book.  We recommend this License
principally for works whose purpose is instruction or reference.


1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
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world-wide, royalty-free license, unlimited in duration, to use that
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A "Modified Version" of the Document means any work containing the
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A "Secondary Section" is a named appendix or a front-matter section of
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HTML, PostScript or PDF designed for human modification.  Examples of
transparent image formats include PNG, XCF and JPG.  Opaque formats
include proprietary formats that can be read and edited only by
proprietary word processors, SGML or XML for which the DTD and/or
processing tools are not generally available, and the
machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page.  For works in
formats which do not have any title page as such, "Title Page" means
the text near the most prominent appearance of the work's title,
preceding the beginning of the body of the text.

The "publisher" means any person or entity that distributes copies of
the Document to the public.

A section "Entitled XYZ" means a named subunit of the Document whose
title either is precisely XYZ or contains XYZ in parentheses following
text that translates XYZ in another language.  (Here XYZ stands for a
specific section name mentioned below, such as "Acknowledgements",
"Dedications", "Endorsements", or "History".)  To "Preserve the Title"
of such a section when you modify the Document means that it remains a
section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document.  These Warranty
Disclaimers are considered to be included by reference in this
License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and has
no effect on the meaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no
other conditions whatsoever to those of this License.  You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute.  However, you may accept
compensation in exchange for copies.  If you distribute a large enough
number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and
you may publicly display copies.


3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document's license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover.  Both covers must also clearly and legibly identify
you as the publisher of these copies.  The front cover must present
the full title with all words of the title equally prominent and
visible.  You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.

If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a computer-network location from which the general network-using
public has access to download using public-standard network protocols
a complete Transparent copy of the Document, free of added material.
If you use the latter option, you must take reasonably prudent steps,
when you begin distribution of Opaque copies in quantity, to ensure
that this Transparent copy will remain thus accessible at the stated
location until at least one year after the last time you distribute an
Opaque copy (directly or through your agents or retailers) of that
edition to the public.

It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to
give them a chance to provide you with an updated version of the
Document.


4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it.  In addition, you must do these things in the Modified Version:

A. Use in the Title Page (and on the covers, if any) a title distinct
   from that of the Document, and from those of previous versions
   (which should, if there were any, be listed in the History section
   of the Document).  You may use the same title as a previous version
   if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities
   responsible for authorship of the modifications in the Modified
   Version, together with at least five of the principal authors of the
   Document (all of its principal authors, if it has fewer than five),
   unless they release you from this requirement.
C. State on the Title page the name of the publisher of the
   Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
   adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license notice
   giving the public permission to use the Modified Version under the
   terms of this License, in the form shown in the Addendum below.
G. Preserve in that license notice the full lists of Invariant Sections
   and required Cover Texts given in the Document's license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title, and add
   to it an item stating at least the title, year, new authors, and
   publisher of the Modified Version as given on the Title Page.  If
   there is no section Entitled "History" in the Document, create one
   stating the title, year, authors, and publisher of the Document as
   given on its Title Page, then add an item describing the Modified
   Version as stated in the previous sentence.
J. Preserve the network location, if any, given in the Document for
   public access to a Transparent copy of the Document, and likewise
   the network locations given in the Document for previous versions
   it was based on.  These may be placed in the "History" section.
   You may omit a network location for a work that was published at
   least four years before the Document itself, or if the original
   publisher of the version it refers to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
   Preserve the Title of the section, and preserve in the section all
   the substance and tone of each of the contributor acknowledgements
   and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
   unaltered in their text and in their titles.  Section numbers
   or the equivalent are not considered part of the section titles.
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