Highlight the selected line in polls

www/poll/app-poll.less

@@ -18,6 +18,7 @@
 @poll-th-user-bg: darken(@poll-th-bg, 10%);
 @poll-editing: lighten(@poll-th-bg, 10%);
 @poll-winner: darken(@poll-th-bg, 15%);
+@poll-highlighted: lighten(@poll-th-bg, 15%);
 @poll-td-bg: @poll-th-bg;
 @poll-td-fg: @poll-th-fg;
 
@@ -514,6 +515,13 @@ div.cp-app-poll-realtime {
                     }
                 }
             }
+            tr:not(:last-child) {
+                &:hover {
+                    td:first-child {
+                        background-color: @poll-highlighted;
+                    }
+                }
+            }
         }
         .cp-app-poll-table-edit {
             //color: @poll-cover-color;