modify css of grid preview

src/client/styles/scss/_on-edit.scss

@@ -338,13 +338,14 @@ body.on-edit {
   .mobile-preview {
     .row {
       height: 100%;
-      padding: 5px;
+      margin: 0px;
     }
   }
   .desktop-preview {
     height: 400px;
     .row {
       div {
+        padding: 0px;
         background-color: $info;
       }
     }
@@ -354,6 +355,7 @@ body.on-edit {
     height: 380px;
     .row {
       div {
+        padding: 0px;
         background-color: $purple;
       }
     }
@@ -364,6 +366,7 @@ body.on-edit {
     height: 280px;
     .row {
       div {
+        padding: 0px;
         background-color: $pink;
       }
     }