Add missing comment-link styles to header

Author: BigBlueHat

www/_partials/header.html

@@ -86,6 +86,13 @@
   margin-left: 2em;
 }
 
+.comment-link {
+  display: none;
+}
+.comment:hover .comment-link {
+  display: inline;
+}
+
 div.proposal {
   padding: 15px;
   margin: 20px 0px 20px 0px;