Add main menu, basic layout

themes/kosmos-22/layouts/_default/single.html

@@ -1,6 +1,10 @@
 {{ define "main" }}
-  <header>
-    <h2>{{ .Title }}</h1>
+  <div class="w-full h-32 bg-[url('/img/lagoon-close-02.jpg')]
+              bg-[center_top_30rem] bg-cover">
+  </div>
+  <div class="max-w-5xl mx-auto -mt-12 py-8 px-8 text-left bg-white">
+  <header class="mb-8">
+    <h2 class="text-2xl font-bold">{{ .Title }}</h1>
   </header>
   <div class="content">
     {{ .Content }}