docs/assets/js/src/vars.js

const codeblocks = document.querySelectorAll(".highlight")

for (const codeblock of codeblocks) {
  codeblock.innerHTML = codeblock.innerHTML
    .replaceAll(
      /<([A-Z_]+)>/g,
      `<var class="text-violet-light dark:text-violet-dark"
        >$1</var>`
    )
}