<div class="collapse proof">
<input type="checkbox" id="{{ include.id }}" class="collapse-toggle"/>
<label for="{{ include.id }}">{{ include.label | default: "Proof" }}</label>
<div class="collapse-hidden" markdown="1">
<div class="collapse-starts"></div>
<label for="{{ include.id }}">{{ include.label | default: "Proof" }}.</label>