Add retro theme

themes/lhs-retro/layouts/partials/header.html

@@ -0,0 +1,13 @@
+{{ with resources.Get "images/rose_logo.jpg" }}
+<h1><a href="{{ absURL "" }}"><img src="{{ .RelPermalink }}" alt="The logo of Leigh Hackspace" width="70px"></a> Leigh Hackspace</h1>
+{{ end }}
+<p>
+    {{ $menu_items := add (len site.Menus.main) -1 }}
+    {{- range $i, $e := site.Menus.main }}
+    <a href="{{ .URL }}" class="active navbar-item has-shadow is-size-5">{{ .Name }}</a>{{ if lt $i $menu_items }} / {{
+    end }}
+    </a>
+    {{- end }}
+</p>
+<hr>
+<h2>{{ .Title }}</h2>