mkdocs-material/material/nav.html

{% if nav_item.children %}
  <li>
    <hr>
    <span class="section">{{ nav_item.title }}</span>
    <ul>
      {% for nav_item in nav_item.children %}
        {% include 'nav.html' %}
      {% endfor %}
    </ul>
  </li>
{% else %}
  <li>
    <a class="{% if nav_item.active %}current{% endif %}" title="{{ nav_item.title }}" href="{{ nav_item.url }}">
      {{ nav_item.title }}
    </a>
    {% if nav_item == current_page %}
      <ul>
        {% for toc_item in toc %}
          {% if h1 %}
            {% for toc_item in toc_item.children %}
              <li class="anchor">
                <a title="{{ toc_item.title }}" href="{{ toc_item.url }}">
                  {{ toc_item.title }}
                </a>
              </li>
            {% endfor %}
          {% else %}
          <li class="anchor">
            <a title="{{ toc_item.title }}" href="{{ toc_item.url }}">
              {{ toc_item.title }}
            </a>
          </li>
          {% endif %}
        {% endfor %}
      </ul>
    {% endif %}
  </li>
{% endif %}