themes/kube/layouts/partials/header.html

<div class="show-sm">
    <div id="nav-toggle-box">
      <div id="nav-toggle-brand">
        <a href="/">{{ .Site.Title }}</a>
      </div><a data-component="toggleme" data-target="#top" href="#" id="nav-toggle"><i class="kube-menu"></i></a>
    </div>
  </div>
  <div class="hide-sm" id="top">
    <div id="top-brand">
      <a href="/" title="home">{{ .Site.Title }}</a>
    </div>
    <nav id="top-nav-main">
      <ul>
       {{ $currentPage := . }}
       {{ range .Site.Menus.main }}
    <li><a href="{{ .URL }}" {{if  $currentPage.IsMenuCurrent "main" . }} class="active"{{end}}>{{ .Name }}</a></li>
    {{end}}
      </ul>
    </nav>
    <nav id="top-nav-extra"> 
      <ul>
        {{ range .Site.Menus.extra }} 
          <li>
            <a href="{{ .Permalink }}">{{ .Name }}</a>
          </li>
        {{ end }}  
      </ul>
    </nav>
  </div>