site/_includes/header.html

<header role="banner">
  <div class="grid">
    <div class="unit center-on-mobiles">
      <h1>
        <a href="{{ site.baseurl }}/">
          <span class="sr-only">Apache Calcite</span>
          <img src="{{ site.baseurl }}/img/logo.svg" alt="Calcite Logo">
        </a>
      </h1>
    </div>
    <nav class="main-nav">
      {% include primary-nav-items.html %}
    </nav>
  </div>
</header>