Implemented phase 0 for the POC prototype in the Website service.

Services/Website/Sources/Library/Internal/Pages/NotFoundPage.swift

@@ -47,11 +47,21 @@ extension NotFoundPage: Page {
     // MARK: Properties
 
     var content: some HTML {
-        h1 {
-            localize("notFound.heading", locale: locale)
-        }
-        p {
-            localize("notFound.message", locale: locale)
+        SiteLayout {
+            div(.class("page not-found")) {
+                h1(.class("type-h1")) {
+                    localize("notFound.heading", locale: locale)
+                }
+                p(.class("type-lead")) {
+                    localize("notFound.message", locale: locale)
+                }
+                a(
+                    .class("button button--dark"),
+                    .href(.Route.home)
+                ) {
+                    "Back to browsing"
+                }
+            }
         }
     }