hugo-theme-relearn/layouts/partials/menu.html

    <nav id="sidebar" class="{{ if $.Site.Params.showVisitedLinks }}showVisitedLinks{{ end }}">
      {{- $currentNode := . }}
      {{- $showvisitedlinks := .Site.Params.showVisitedLinks }}
      <div id="header-wrapper">
        <div id="header">
{{ partial "logo.html" . }}
        </div>
        {{- if not .Site.Params.disableSearch }}
{{ partial "search.html" . }}
        {{- end }}
      </div>
      {{- if not .Site.Params.disableLandingPageButton }}
      <section id="homelinks">
        <ul>
          <li>
              <a class="padding" href="{{ .Site.Params.landingPageURL | default "/" | relLangURL }}">{{ .Site.Params.landingPageName | default `<i class="fas fa-home"></i> Home` | safeHTML }}</a>
          </li>
        </ul>
      </section>
      {{- end }}
      <div class="highlightable">
        <ul class="topics">
          {{- if eq .Site.Params.ordersectionsby "title" }}
            {{- range .Site.Home.Sections.ByTitle }}
            {{- template "section-tree-nav" dict "sect" . "currentnode" $currentNode "showvisitedlinks" $showvisitedlinks "alwaysopen" false }}
            {{- end }}
          {{- else }}
            {{- range .Site.Home.Sections.ByWeight }}
            {{- template "section-tree-nav" dict "sect" . "currentnode" $currentNode "showvisitedlinks" $showvisitedlinks "alwaysopen" false }}
            {{- end }}
          {{- end }}
        </ul>
        {{- $disableShortcutsTitle := .Site.Params.DisableShortcutsTitle }}
        {{- with .Site.Menus.shortcuts }}
        <section id="shortcuts">
          <h3>{{ if not $disableShortcutsTitle }}{{ T "Shortcuts-Title" }}{{ end }}</h3>
          <ul>
            {{- range sort . "Weight" }}
            <li>
              {{ .Pre }}<a class="padding" href="{{ .URL | absLangURL }}">{{ safeHTML .Name }}</a>{{ .Post }}
            </li>
            {{- end }}
          </ul>
        </section>
        {{- end }}

        {{- if or .Site.IsMultiLingual $showvisitedlinks }}
        <section id="prefooter">
          <hr/>
          <ul>
            {{- if and .Site.IsMultiLingual (not .Site.Params.DisableLanguageSwitchingButton) }}
            <li>
              <a class="padding">
                <i class="fas fa-language fa-fw"></i>
                <div class="select-style">
                  <select id="select-language" onchange="location = this.value;">
                    {{- $siteLanguages := .Site.Languages }}
                    {{- $pageLang := .Page.Lang }}
                    {{- range .Page.AllTranslations }}
                      {{- $translation := . }}
                      {{- range $siteLanguages }}
                        {{- if eq $translation.Lang .Lang }}
                          {{- $selected := false }}
                          {{- if eq $pageLang .Lang }}
                    <option id="{{ $translation.Language }}" value="{{ $translation.Permalink }}" selected>{{ .LanguageName }}</option>
                          {{- else }}
                    <option id="{{ $translation.Language }}" value="{{ $translation.Permalink }}">{{ .LanguageName }}</option>
                          {{- end }}
                        {{- end }}
                      {{- end }}
                    {{- end }}
                  </select>
                  <svg version="1.1" id="Capa_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
                    width="255px" height="255px" viewBox="0 0 255 255" style="enable-background:new 0 0 255 255;" xml:space="preserve">
                    <g>
                      <g id="arrow-drop-down">
                        <polygon points="0,63.75 127.5,191.25 255,63.75 		" />
                      </g>
                    </g>
                  </svg>
                </div>
              </a>
            </li>
            {{- end }}

            {{- if $showvisitedlinks }}
            <li><a class="padding" href="#" data-clear-history-toggle=""><i class="fas fa-history fa-fw"></i> {{ T "Clear-History" }}</a></li>
            {{- end }}
          </ul>
        </section>
        {{- end }}
        <section id="footer">
          {{- partial "menu-footer.html" . }}
        </section>
      </div>
    </nav>
    {{- define "section-tree-nav" }}
    {{- $showvisitedlinks := .showvisitedlinks }}
    {{- $currentNode := .currentnode }}
    {{- $currentFileUniqueID := "" }}
    {{- $alwaysopen := .alwaysopen }}
    {{- with $currentNode.File }}{{ $currentFileUniqueID = .UniqueID }}{{ end }}
      {{- with .sect }}
        {{- $hidden := and (eq (.Scratch.Get "relearnIsHiddenFromCurrent") true) (not $.showhidden) (not (.IsAncestor $currentNode)) }}
        {{- if $hidden }}
        {{- else if .IsSection }}
          {{- safeHTML .Params.head }}
          {{- $currentAlwaysopen := .Params.alwaysopen | default $alwaysopen }}
          <li data-nav-id="{{.RelPermalink}}" title="{{.Title}}" class="dd-item{{if eq .File.UniqueID $currentFileUniqueID}} active{{end}}{{if .IsAncestor $currentNode }} parent{{end}}{{if $currentAlwaysopen}} alwaysopen{{end}}">
            <a href="{{.RelPermalink}}">
              {{ partial "menu-pre.html" . }}{{ or .Params.menuTitle .LinkTitle .Title }}{{ partial "menu-post.html" . }}
              {{ if $showvisitedlinks }}<i class="fas fa-check read-icon"></i>{{ end }}
            </a>
            <ul>
              {{- $currentNode.Scratch.Set "pages" .Pages }}
              {{- if .Sections}}
                {{- $currentNode.Scratch.Set "pages" (.Pages | union .Sections) }}
              {{- end }}
              {{- $pages := ($currentNode.Scratch.Get "pages") }}
              {{- if eq .Site.Params.ordersectionsby "title" }}
                {{- range $pages.ByTitle }}
                  {{- template "section-tree-nav" dict "sect" . "currentnode" $currentNode "showvisitedlinks" $showvisitedlinks "alwaysopen" true}}
                {{- end }}
              {{- else }}
                {{- range $pages.ByWeight }}
                {{- template "section-tree-nav" dict "sect" . "currentnode" $currentNode "showvisitedlinks" $showvisitedlinks "alwaysopen" true}}
                {{- end }}
              {{- end }}
            </ul>
          </li>
        {{- else }}
          <li data-nav-id="{{.RelPermalink}}" title="{{.Title}}" class="dd-item{{if eq .File.UniqueID $currentFileUniqueID}} active{{end}}">
            <a href="{{.RelPermalink}}">
              {{ partial "menu-pre.html" . }}{{ or .Params.menuTitle .LinkTitle .Title }}{{ partial "menu-post.html" . }}
              {{ if $showvisitedlinks }}<i class="fas fa-check read-icon"></i>{{ end }}
            </a>
          </li>
        {{- end }}
      {{- end }}
    {{- end }}