added fixed width for simplenews node type

sites/all/themes/gui/materiobasetheme/scss/layout.scss

@@ -210,7 +210,8 @@ body.page-node-11175,
 body.page-node-12324,
 body.page-user,
 body.page-node-11186,
-body.page-cart{
+body.page-cart,
+body.node-type-simplenews{
   #header>.inner, #utilities>.inner, #center, #footer{
     @include grid-row();
   }