<section class=“navigation”>

<nav>
  {% if site.data.navigation.items.size > 0 %}
  <ul class="main">
    {% for item in site.data.navigation.items %}
    <li {% if page.navItemTitle == item.title %}class="active"{% endif %}><a href="{{ item.url | prepend:site.baseurl }}">{{ item.title }}</a>
      {% if item.subitems.size > 0 %}
      <ul class="sub">
        {% for sitem in item.subitems %}
        <li><a href="{{ sitem.url | prepend:site.baseurl }}">{{ sitem.title }}</a></li>
        {% endfor %}
      </ul>
      {% endif %}
    </li>
    {% endfor %}
  </ul>
  {% else %}
  <ul>
    <li>NOTICE: There're no items. You can add them on <code>_data/navigation</code>.</li>
  </ul>
  {% endif %}
</nav>

</section>