Fix margin(left, right) #30

Author: ishikawa999

assets/stylesheets/custom_messages.css

@@ -42,5 +42,5 @@ div.message-customize-menu {
 div.message-customize-menu p {
   color: gray;
   font-size: 10px;
-  margin: 5px;
+  margin: 5px 0px;
 }