_header.twig

<header role="banner">
    <div aria-labelledby="osu_navbar_heading" id="osu_navbar" role="navigation">
      <h2 class="osu-semantic" id="osu_navbar_heading">Ohio State nav bar</h2>

      <div class="container">
        <div class="univ_info">
          <p class="univ_name"><a href="http://osu.edu" title="The Ohio State University">The Ohio State University</a></p>
        </div>
        <!-- /univ_info -->

        <div class="univ_links">
          <div class="links">
            <ul>
              <li><a class="help" href="http://www.osu.edu/help.php">Help</a></li>
              <li><a class="buckeyelink" href="http://buckeyelink.osu.edu/">BuckeyeLink</a></li>
              <li><a class="map" href="http://www.osu.edu/map/">Map</a></li>
              <li><a class="findpeople" href="http://www.osu.edu/findpeople.php">Find People</a></li>
              <li><a class="webmail" href="https://email.osu.edu/">Webmail</a></li>
              <li><a class="search" href="http://www.osu.edu/search/">Search Ohio State</a></li>
            </ul>
          </div>
        </div>
      </div>
    </div>

    <div class="container">
      <div id="header-logos">
        <a href="/" class="dep-logo">
          <img alt="{{ site_name }}" title="{{ site_name }}" src="/sites/default/files/logos/department-logo.svg" id="dep-logo-img" />
        </a>

        <a href="https://artsandsciences.osu.edu/" class="osu-logo">
          {% if not osu_logo %}
            <img alt="College of Arts and Sciences logo" title="College of Arts and Sciences logo" src="/themes/asc_bootstrap/images/logos/asc-logo.svg"  id="asc-logo-img" />
          {% elseif osu_logo %}
            <img alt="The Ohio State University logo" title="The Ohio State University logo" src="/themes/asc_bootstrap/images/logos/osu-logo.svg" onerror="this.style.display='none'" id="osu-logo-img" />
          {% endif %}
        </a>
      </div>
      <div id="header-logos-mobile">
        <a href="https://artsandsciences.osu.edu/" class="osu-logo">
          {% if not osu_logo %}
            <img alt="College of Arts and Sciences logo" title="College of Arts and Sciences logo" src="/themes/asc_bootstrap/images/logos/asc-logo-mobile.svg" id="asc-logo-img-mobile" />
          {% elseif osu_logo %}
            <img alt="The Ohio State University logo" title="The Ohio State University logo" src="/themes/asc_bootstrap/images/logos/osu-logo-mobile.svg" onerror="this.style.display='none'" id="osu-logo-img-mobile" />
          {% endif %}
        </a>
        <a href="/" class="dep-logo">
          <img alt="{{ site_name }}" title="{{ site_name }}" src="/sites/default/files/logos/department-logo-mobile.svg" id="dep-logo-img" />
        </a>
      </div>
    </div>
<div class="container">
    {% if page.header %}
        {% block header %}

            {{ page.header }}

        {% endblock %}
      {% endif %}
</div>
  </header>