message: Add styles for scrollbars in long code blocks.
diff: @@ -184,6 +184,17 @@ export const Reader = ({ entityId, onReady }: Props) => {
  }
  `,
  }),
  + injectCss({
  + // Properly style code blocks.
  + css: `
  + .md-typeset pre > code::-webkit-scrollbar-thumb {
  + background-color: hsla(0, 0%, 0%, 0.32);
  + }
  + .md-typeset pre > code::-webkit-scrollbar-thumb:hover {
  + background-color: hsla(0, 0%, 0%, 0.87);
  + }
  + `,
  + }),
  injectCss({
  // Admonitions and others are using SVG masks to define icons. These
  // masks are defined as CSS variables.
  