Add "main" menu to the site header

Based on "Menu Templates" (https://gohugo.io/templates/menu-templates/)

layouts/_default/list.html

@@ -6,9 +6,14 @@
 <main>
     <div>
         <h1 id="title">{{ .Title }}</h1>
-        {{ range .Pages }}
-        {{ .Render "summary"}}
-        {{ end }}
+	<div class="list-content">
+	    {{ .Content }}
+	</div>
+	<div class="list-summary">
+            {{ range .Pages }}
+            {{ .Render "summary"}}
+            {{ end }}
+	</div>
     </div>
 </main>
 {{ end }}

layouts/_default/summary.html

@@ -4,9 +4,11 @@
         <div class="post-meta">{{ .Date.Format "Mon, Jan 2, 2006" }} - {{ .FuzzyWordCount }} Words </div>
     </header>
     {{ .Summary }}
+    {{ if .Truncated }}
     <footer>
         <a href='{{ .Permalink }}'>
             <span style="white-space: nowrap;">Read more →</span>
         </a>
     </footer>
+    {{ end }}
 </article>

layouts/partials/header.html

@@ -1,2 +1,31 @@
 <header>
+    <nav>
+        <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>
 </header>