增加对话框按钮点击效果.code review by LZF

@@ -320,5 +320,9 @@ $suggest: sprite-map("me/suggest/*.png",$spacing: 5px);
                 color: #ee0011;
                 color: #ee0011;
             }
             }
         }
         }
+
+        > span:active {
+            background-color: #ccc;
+        }
     }
     }
 }
 }