[% SET
  navbar = [
    {
      title = 'Home',
      url   = 'index.html',
    },
    {
      title = 'Topic 1',
      url   = 'topic1.html',
      sub_pages = [
        {
          title = 'Topic 1a',
          url   = 'topic1a.html',
        },
      ]
    },
  ]
%]

##</code><code>##

  <div class="navbar-level1">
  [% FOREACH n1 = NavBar.navbar %]
    [% PROCESS navbarentry
               nav = n1 %]
    [% IF n1.sub_level %]
      <div class="navbar-level2">
      [% FOREACH n2 = n1.sub_level %]
        [% PROCESS navbarentry
                   nav = n2 %]
        ...
      [% END %]
      </div>
    [% END %]
  [% END %]
  </div>

##</code><code>##

  <a[% IF url %] href="[% url %]"[% END %][% IF active %] class="active"[% END %]>