fix css typo in ratings on detail page

Author: ngokevin

media/css/mkt/detail.less

@@ -451,7 +451,7 @@ h1 .num {
 
     #reviews-detail {
         min-height: 290px;
-        margin-top: 40px 0 20px;
+        margin: 40px 0 20px;
 
         .review-stars-header {
             clear: right;