Explanation of John's Fork.

Modus themes is the slowest to load package on my system, so I'm trying to remove bits that I don't use in hopes of making this run a bit faster.

Modus themes for GNU Emacs (Modus Operandi and Modus Vivendi)

A pair of highly accessible themes that conform with the WCAG AAA standard for colour contrast between background and foreground combinations (a minimum contrast of 7:1---the highest standard of its kind). The Modus themes also strive to empower users with red-green color deficiency: this is achieved through customisation options that replace all relevant instances of green with blue, as well as the overall design of the themes which relies mostly on colours that cover the blue-cyan-magenta side of the spectrum.

The themes are built into GNU Emacs 28 (development target). They are also distributed in several packages formats.

• modus-operandi is light.
• modus-vivendi is dark.

For some demo content, check:

• The screenshots of the themes https://protesilaos.com/emacs/modus-themes-pictures/.
• My videos on Emacs https://protesilaos.com/code-casts/.

Quick setup for the latest version

Built-in version

For the themes that are built into Emacs you cannot require the package. Use the following instead.

With use-package:

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

Without use-package:

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

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

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

Packaged version

With use-package:

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

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

Without use-package:

(require 'modus-themes)

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

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

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

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

Note: make sure that you do not customise custom-theme-load-path or custom-theme-directory after the themes' package declaration. That will lead to failures in loading the files. If you must change those variables, do it before the package declaration.

All customisations in short

While you should read the manual for all the details (see next section), here is a snippet with all current customisation options and their possible values. Note that those settings are only for purposes of demonstration:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Further information

Read the Info manual HTML version for how to install, load, enable, and customise the themes. If you are using the latest version of the themes, you already have the manual installed: evaluate (info "(modus-themes) Top") to start reading it.

The themes cover a broad range of packages and are highly customisable.