vendure/docs/layouts/partials/menu-filetree.html

<ul>
    <li>
    <ul><li><a href="/getting-started" {{- if eq .Page.Title "Getting Started" }} class="text-blue-700 active"{{ end }}>
      Getting Started
    </a></li></ul>
    </li>
    <li>{{ template "book-section" (dict "Section" .Site.Sections "CurrentPage" $.Permalink) }}</li>
</ul>

{{ define "book-section" }} <!-- Single section of menu (recursive) -->
<ul {{ if .Expanded }}class="expanded"{{ end }}>
    {{ range (.Section.ByParam "Title").ByParam "Weight" }}
        {{ if ne .Title "Search Index" }}
            {{ if and (eq .Kind "section") (or (gt (len .Pages) 0) (gt (len .Sections) 0) ) }}
                <li class="section">
                    {{ $expanded := in $.CurrentPage .Permalink }}
                    <div class="section-link">
                        <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" class="w-6 h-6 section-icon {{ if $expanded}}expanded{{ end }}">
                          <path stroke-linecap="round" stroke-linejoin="round" d="M4.5 15.75l7.5-7.5 7.5 7.5" />
                        </svg>
                        {{ template "book-page-link" (dict "Page" . "CurrentPage" $.CurrentPage) }}
                    </div>
                    {{ template "book-section" (dict "Section" .Pages "CurrentPage" $.CurrentPage "Expanded" $expanded) }}
                </li>
            {{ else }}
                <li>
                    {{ template "book-page-link" (dict "Page" . "CurrentPage" $.CurrentPage) }}
                </li>
            {{ end }}
        {{end }}
    {{ end }}
  </ul>
{{ end }}

{{ define "book-page-link" }}
{{- with .Page -}}
<a href="{{ .RelPermalink }}" {{- if eq $.CurrentPage .Permalink }} class="text-blue-700 active"{{ end }}>
  {{- template "title" . -}}
</a>
{{- end -}}
{{ end }}