<nav class="menu">
  <ul>
    {{ $currentPage := . }}
    {{ range .Site.Menus.main }}
        {{ if .HasChildren }}
            <li class="{{ if $currentPage.HasMenuCurrent "main" . }}active{{ end }}">
                <a href="#">
                    {{ .Pre }}
                    <span>{{ .Name }}</span>
                </a>
            </li>
            <ul class="sub-menu">
                {{ range .Children }}
                    <li class="{{ if $currentPage.IsMenuCurrent "main" . }}active{{ end }}">
                        <a href="{{ .URL }}">{{ .Name }}</a>
                    </li>
                {{ end }}
            </ul>
        {{ else }}
            <li>
                <a href="{{ .URL }}">
                    {{ .Pre }}
                    <span>{{ .Name }}</span>
                </a>
            </li>
        {{ end }}
    {{ end }}
  </ul>
</nav>