Note on display-fill-column-indicator-mode ​

The display-fill-column-indicator-mode uses a typographic character to draw its line. This has the downside of creating a dashed line. The dashes are further apart depending on how tall the font’s glyph height is and what integer the line-spacing is set to.

At the theme level we eliminate this effect by making the character one pixel tall: the line is contiguous. Users who prefer the dashed line are advised to change the fill-column-indicator face, as explained elsewhere in this document. For example:

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

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

To make the line thicker, set the height to be equal to the base font size instead of the one pixel we use. This is done by specifying a rate instead of an absolute number, as in ‘:height 1.0’ versus ‘:height 1’. For example:

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