Make it possible to customize post highlight colour with css

app/assets/javascripts/discourse/views/topic_view.js

@@ -413,9 +413,11 @@ Discourse.TopicView.reopenClass({
 
           $contents.data("orig-color", origColor);
           $contents
-            .css({ backgroundColor: "#ffffcc" })
+            .addClass('highlighted')
             .stop()
-            .animate({ backgroundColor: origColor }, 2500);
+            .animate({ backgroundColor: origColor }, 2500, 'swing', function(){
+              $contents.removeClass('highlighted');
+            });
         }
       }
     });

app/assets/stylesheets/application/topic-post.css.scss

@@ -563,6 +563,9 @@
             margin: 0 0 5px 0;
           }
         }
+        &.highlighted {
+          background-color: $highlight;
+        }
       }
       .contents.bottom-round {
         overflow: hidden;