docs/python_docs/themes/mx-theme/mxtheme/header_search.html

{%- if pagename != "search" %}
<form class="form-inline pull-sm-right" action="{{ pathto('search') }}" method="get">
      <div class="mdl-textfield mdl-js-textfield mdl-textfield--expandable mdl-textfield--floating-label mdl-textfield--align-right">
        <label id="quick-search-icon" class="mdl-button mdl-js-button mdl-button--icon"  for="waterfall-exp">
          <i class="material-icons">search</i>
        </label>
        <div class="mdl-textfield__expandable-holder">
          <input class="mdl-textfield__input" type="text" name="q"  id="waterfall-exp" placeholder="Search" />
          <input type="hidden" name="check_keywords" value="yes" />
          <input type="hidden" name="area" value="default" />
        </div>
      </div>
      <div class="mdl-tooltip" data-mdl-for="quick-search-icon">
      {{ _('Quick search') }}
      </div>
</form>
{%- endif %}