added final navigation bar (#9)

Reviewed-on: #9

frontend/src/style.css

@@ -1,3 +1,9 @@
+:root{
+  -webkit-user-select: none; /* Safari */
+  -ms-user-select: none; /* IE 10 and IE 11 */
+  user-select: none; /* Standard syntax */
+}
+
 html, body {
 	position: relative;
 	width: 100%;