src/_includes/header.html

<header role="banner">
  <nav class="mobile-nav show-on-mobiles">
    {% include primary-nav-items.html %}
  </nav>
  <div class="grid">
    <div class="unit one-third center-on-mobiles">
      <h1>
        <a href="/">
          <span class="sr-only">Apache Mnemonic</span>
          <img src="/img/mnemonic_logo.png" width="289" alt="Mnemonic Logo" class="logo">
        </a>
      </h1>
    </div>
    <nav class="main-nav unit two-thirds hide-on-mobiles">
      {% include primary-nav-items.html %}
    </nav>
  </div>
  <!-- Return to Top -->
  <a href="#top" id="return-to-top"><i class="fa fa-chevron-up"></i></a>
</header>