hugo-coder/layouts/shortcodes/tab.html

{{ $group := .Page.Scratch.Get "tabGroupIndex" | default 0 }}
{{ $index := .Page.Scratch.Get "tabElementIndex" | default 0 }}
{{ $name := .Get "name" | default "Name Me!" }}

<style>
  .tabs input#tab-{{ $group }}-{{ $index }}:checked ~ .tab-content-{{ $group }}-{{ $index }} {
    display: block;
  }
</style>

<input type="radio" class="tab-input" name="tab-select-{{ $group }}" id="tab-{{ $group }}-{{ $index }}" {{ if eq $index 0 }}checked{{ end }}/>
<label for="tab-{{ $group }}-{{ $index }}" class="tab-label">{{ $name }}</label>
<div class="tab-content tab-content-{{ $group }}-{{ $index }}">
  {{ .Inner | markdownify }}
</div>

{{ .Page.Scratch.Set "tabElementIndex" (add 1 $index) }}