docs/theme/mkdocs/nav.html

<nav id="nav_menu" class="clearfix navbar navbar-default navbar-static-top affix" role="navigation">
  <div id="docsnav">
    <ul id="main-nav" class="pull-left">
      {% for menu in nav %}
      {% if menu.title != '**HIDDEN**' %}
      <li class="dd_menu pull-left{% if menu.active %} active{% endif %}">
        {% for first_item in menu.children[:1] %}
        <a href="{{ first_item.url }}">{{ menu.title }}</a>
        {% endfor %}
        <ul class="dd_submenu" style="max-height: 75px;">
        {% for menu in menu.children %}
          <li {% if menu.active %}class="active"{% endif %}>
            <a href="{{ menu.url }}">{{ menu.title }}</a>
          </li>
        {% endfor %}
        </ul>
      </li>
      {% endif %}
      {% endfor %}
    </ul>
    <form id="nav_search" class="pull-right" action="/jsearch/">
      <span role="status" aria-live="polite" class="ui-helper-hidden-accessible"></span>
      <input name="q" id="tipue_search_input" type="text" class="search_input search-query ui-autocomplete-input" placeholder="Search the Docs" autocomplete="off">
    </form>
  </div>
</nav>