few tweaks to help page

docs/mandoc.css

@@ -11,10 +11,13 @@
 /* Global defaults. */
 
 html {		max-width: 65em;
+		background: #305;
 		--bg: #002;
 		--fg: #dde; }
 body {		background: var(--bg);
 		color: var(--fg);
+		margin: 2em;
+		padding: 1em;
 		font-size: 18px;
 		font-family: Helvetica,Arial,sans-serif; }
 a { color: var(--fg); }

web.go

@@ -1451,8 +1451,8 @@ func serveasset(w http.ResponseWriter, r *http.Request) {
 }
 func servehelp(w http.ResponseWriter, r *http.Request) {
 	name := mux.Vars(r)["name"]
-	w.Header().Set("Cache-Control", "max-age=0")
-	http.ServeFile(w, r, "docs/" + name)
+	w.Header().Set("Cache-Control", "max-age=600")
+	http.ServeFile(w, r, "docs/"+name)
 }
 func servehtml(w http.ResponseWriter, r *http.Request) {
 	templinfo := getInfo(r)