<header class=“header small”>

<span class="title">
  <a href="{{ '/' | relative_url }}">{{ site.title }} <small class=subtitle></small></a>
</span>
<nav class="header-nav">
  <ul>
    {% for nav in site.nav %}
    <li>
      {% if nav.url contains 'http://' or nav.url contains 'https://' %}
      <a href="{{ nav.url }}">{{ nav.name }}</a>
      {% else %}
      <a href="{{ nav.url | relative_url }}">{{ nav.name }}</a>
      {% endif %}
    </li>
    {% endfor %}
  </ul>
</nav>

</header>