<div class="book-expand">
  <label>
    <div class="book-expand-head flex justify-between">
      <span>{{ default "Expand" (.Get 0) }}</span>
      <span>{{ default "↕" (.Get 1) }}</span>
    </div>
    <input type="checkbox" class="hidden" />
    <div class="book-expand-content markdown-inner">
      {{ .Inner | markdownify }}
    </div>
  </label>
</div>