GitHub custom font

github-font.user.css

/* ==UserStyle==
@name           GitHub Font
@namespace      github.com/mskelton
@version        1.2.0
@description    Uses custom font for GitHub code blocks/editors.
@author         Mark Skelton
@license        ISC
@homepageURL    https://gist.github.com/mskelton/b93904fb16588d3c4ac7f038ee14249f
==/UserStyle== */
@-moz-document domain("github.com"), domain("gist.github.com") {

  @font-face {
    font-family: termicons;
    src: local("termicons");
    unicode-range: U+D000-D200;
  }

  .blob-code-inner,
  .blob-num,
  .highlight pre {
    font-family: termicons, "JetBrains Mono" !important;
  }

  .pl-c {
    font-style: italic;
  }
}