mat.services/sass/style/parts/_code.scss

code {
  background-color: var(--bg-1);
  padding: 0.1em 0.2em;
  border-radius: 5px;
  border: 1px solid var(--border-color);
  font-family: var(--code-font);
}

pre {
  /* Rounded border */
  border-radius: 5px;
  border: 1px solid var(--border-color);

  line-height: 1.4;
  overflow-x: auto;
  padding: 1em;
}

pre code {
  background-color: transparent;
  color: inherit;
  font-size: 100%;
  padding: 0;

  // We only want a border around `code` and not `pre code` blocks.
  border: 0;
}

pre {
  font-family: var(--code-font);
  position: relative;
}

pre code[class*="language-"]::before {
  background: black;
  border-radius: 0 0 0.25rem 0.25rem;
  color: white;
  font-size: 12px;
  letter-spacing: 0.025rem;
  padding: 0.1rem 0.5rem;
  position: absolute;
  right: 0.1rem;
  margin-top: 0.1rem;
  text-align: right;
  text-transform: uppercase;
  top: 0;
}

pre code[class="language-javaScript"]::before,
pre code[class="language-js"]::before {
  content: "js";
  background: #f7df1e;
  color: black;
}

pre code[class*="language-yml"]::before,
pre code[class*="language-yaml"]::before {
  content: "yaml";
  background: #f71e6a;
  color: white;
}

pre code[class*="language-shell"]::before,
pre code[class*="language-bash"]::before,
pre code[class*="language-sh"]::before {
  content: "shell";
  background: green;
  color: white;
}

pre code[class*="language-json"]::before {
  content: "json";
  background: dodgerblue;
  color: #000000;
}

pre code[class*="language-python"]::before,
pre code[class*="language-py"]::before {
  content: "py";
  background: blue;
  color: yellow;
}

pre code[class*="language-css"]::before {
  content: "css";
  background: cyan;
  color: black;
}

pre code[class*="language-go"]::before {
  content: "Go";
  background: cyan;
  color: royalblue;
}

pre code[class*="language-md"]::before {
  content: "Markdown";
  background: royalblue;
  color: whitesmoke;
}

pre code[class*="language-rust"]::before,
pre code[class*="language-rs"]::before {
  content: "rust";
  background: #fff8f6;
  color: #ff4647;
}

pre code[class*="language-nix"]::before {
  content: "nix";
  background: #5277C3;
  color: snow;
}