return to original 25px from 30px

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

@@ -236,7 +236,7 @@ body.on-edit {
 
     .page-editor-preview-body {
       max-width: 980px;
-      padding: 18px 30px 0;
+      padding: 18px 15px 0;
       overflow-y: scroll;
     }