fixes #3222: simpler positioning of modals

less/modals.less

@@ -23,11 +23,11 @@
 // Base modal
 .modal {
   position: fixed;
-  top: 50%;
+  top: 10%;
   left: 50%;
   z-index: @zindexModal;
   width: 560px;
-  margin: -250px 0 0 -280px;
+  margin-left: -280px;
   background-color: @white;
   border: 1px solid #999;
   border: 1px solid rgba(0,0,0,.3);
@@ -42,7 +42,7 @@
     .transition(e('opacity .3s linear, top .3s ease-out'));
     top: -25%;
   }
-  &.fade.in { top: 50%; }
+  &.fade.in { top: 10%; }
 }
 .modal-header {
   padding: 9px 15px;