AdminLte/docs/_includes/sidebar.html

  <aside class="main-sidebar sidebar-dark-primary elevation-4">
    <a href="{{'index.html' | relative_url}}" class="brand-link logo-switch">
      <img src="{{'assets/img/logo-xs.png' | relative_url}}" alt="AdminLTE Docs Logo Small" class="brand-image-xl logo-xs">
      <img src="{{'assets/img/logo-xl.png' | relative_url}}" alt="AdminLTE Docs Logo Large" class="brand-image-xs logo-xl" style="left: 12px">
    </a>
    <div class="sidebar">
      <nav class="mt-2">
        <ul class="nav nav-pills nav-sidebar nav-child-indent flex-column" data-widget="treeview" role="menu">
         {% for item in site.navigation %}
            {% assign subitem_active = 'false' %}
            {% for subitem in item.subitems %}
              {% assign subitem_url = '/' | append: subitem.url %}
              {% if subitem_url == page.url %}
                {% assign subitem_active = 'true' %}
              {% endif %}
            {% endfor %}

            <li class="nav-item {% if item.subitems %}has-treeview{% endif %} {% if subitem_active == 'true' %}menu-open{% endif %}">
              {% if item.url == 'index.html' %}
                {% assign item_url = '/' %}
              {% else %}
                {% assign item_url = '/' | append: item.url %}
              {% endif %}

              <a href="{% if item.url %}{{item.url | relative_url}}{% else %}#{% endif %}" class="nav-link {% if item_url == page.url %}active{% endif %}{% if subitem_active == 'true'%}active{% endif %}">
                <i class="nav-icon {{item.icon}}"></i>
                <p>
                  {{item.title}}
                  {% if item.subitems %}<i class="right fas fa-angle-left"></i>{% endif %}
                </p>
              </a>

              {% if item.subitems %}
                <ul class="nav nav-treeview">
                {% for subitem in item.subitems %}
                  {% assign subitem_url = '/' | append: subitem.url %}
                  <li class="nav-item">
                    <a href="{{subitem.url | relative_url}}" class="nav-link {% if subitem_url == page.url %}active{% endif %}">
                      <i class="far fa-circle nav-icon"></i>
                      <p>{{subitem.title}}</p>
                    </a>
                  </li>
                {% endfor %}
                </ul>
              {% endif %}
            </li>
         {% endfor %}
        </ul>
      </nav>
    </div>
  </aside>