Common/Frontend/Layout/Repository/Accordion.twig
<div class="panel-group" id="Accordion-{{ Hash }}">
{% for Index, Element in ContentList %}
<div class="panel panel-default">
<div class="panel-heading">
<h3 class="panel-title">
<a class="-underline" data-toggle="collapse" data-parent="#Accordion-{{ Hash }}"
href="#Element-{{ Element.Hash }}">
{{ Element.Header }}
</a>
</h3>
</div>
<div id="Element-{{ Element.Hash }}" class="panel-collapse collapse {% if(Element.Toggle) %}in{% endif %}">
<div class="panel-body" style="overflow: hidden;">
{{ Element.Content }}
</div>
</div>
</div>
{% endfor %}
</div>