xrpl-dev-portal/tool/template-sidebar_nav.html

<div class="guide_toc">
  <div id="sidenav_accordion" class="panel-group" role="tablist" aria-multiselectable="true">
    {% for cat in categories %}
    <div class="panel panel-default{% if currentpage.category == cat %} active{% endif %}">
      <div class="panel-heading" role="tab" id="sidenav_cat_head_{{loop.index}}">
        <h5 class="panel-title">
          <a {% if currentpage.category != cat %}class="collapsed"{% endif %} role="button" data-toggle="collapse" data-parent="#sidenav_accordion" href="#sidenav_collapse_{{loop.index}}" aria-expanded="true" aria-controls="sidenav_collapse_{{loop.index}}">
            {{ cat }}
          </a>
        </h5>
      </div><!-- /.panel-heading -->

      <div id="sidenav_collapse_{{loop.index}}" class="collapse{% if currentpage.category == cat %} in{% endif %}" role="tabpanel" aria-labelledby="sidenav_cat_head_{{loop.index}}">
        <div class="panel-body">
          <ul class="sidebar_cat_pagelist">
          {% set catpages = pages|selectattr("category", "equalto", cat)|list %}
          {% set printed_subcategories = [] %}
          {% for page in catpages %}
            {% if page.subcategory is undefined %}
              {% if page == currentpage %}
              <li><a class="active nosubcat-page" href="{{ page.html }}">{{ page.name }}</a></li>
              {% else %}
              <li><a class="nosubcat-page" href="{{ page.html }}">{{ page.name }}</a></li>
              {% endif %}
            {% elif page.subcategory not in printed_subcategories %}
              {% if page == currentpage %}
              <li><a class="subcat-title active" href="#main_content_body">{{ page.name }}</a></li>
              {% else %}
              <li><a class="subcat-title" href="{{ page.html }}">{{ page.name }}</a></li>
              {% endif %}

              {% for subpage in catpages|selectattr('subcategory', 'equalto', page.subcategory) %}
                {% if subpage != page %}
                {% if subpage == currentpage %}
                <li><a class="active subpage" href="#main_content_body">{{ subpage.name }}</a></li>
                {% else %}
                <li><a class="subpage" href="{{ subpage.html }}">{{ subpage.name }}</a></li>
                {% endif %}
                {% endif %}
              {% endfor %}
              {% set _ = printed_subcategories.append(page.subcategory) %}

            {% endif %}
          {% endfor %}

          </ul>
        </div><!-- /.panel-body -->
      </div><!-- /#sidenav_collapse{{loop.index}} -->

    </div><!-- /.panel -->
    {% endfor %}

  </div><!-- /#sidenav_accordion -->
</div><!-- /.guide_toc -->