Bind 404 error

src/error.ml

@@ -3,7 +3,30 @@ let error_msg code reason = Format.sprintf "<h1>Error: %d - %s</h1>" code reason
 let page code reason =
   let content =
     match code with
-    | 404 -> Format.sprintf {|%s<br />|} (error_msg code reason)
+    | 404 -> {html|
+<style type="text/css">
+body {
+  background-color: black;
+}
+br, hr {
+  display: none;
+}
+h1 {
+  color: rgba(255,255,255,.75);
+  margin: 1.5ex;
+  text-align: center;
+}
+footer {
+  position: fixed;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  text-align: center;
+}
+</style>
+<h1>Error 404</h1>
+<script src="/assets/js/404.js"></script>
+|html}
     | n -> error_msg n reason
   in
   content