{{/* a shortcode that builds a preview of all html samples */}}
<style>
  .code-toolbar {
    margin-bottom: 20px;
  }
  .preview {
    margin-bottom: var(--code-margin) 0;
    padding: 20px;
    border: 1px solid hsla(0,0%,100%,.1);
  }
</style>
<script>
  window.onload = function show_samples() {
    let samples = document.querySelectorAll('pre.language-html');
    for(i=0; i < samples.length; i++) {
      let sample = samples[i];
      let preview = document.createElement('div');

      preview.innerHTML = sample.innerText;
      preview.classList.add("preview");
      sample.parentElement.parentElement.appendChild(preview);
    }
  }
</script>