<nav class=“sidenavigation”>

      <h1> <a href="{{ page.sidenav.mainurl }}"> {{ page.sidenav.mainname }} </a></h1>
      <ul>
{% for link in page.sidenav.links %}
  <li>
                      {% assign link_url = link.url | append: ".html" %}
                      <a class="{% if page.url == link.url or page.url == link_url %}active{% endif %}" href="{{link.url}}">{{link.name}}</a></li>
      {% endfor %}
      </ul>

</nav>