fix(scroll): prevent native webkit scrollbars from showing

scss/_scaffolding.scss

@@ -94,6 +94,11 @@ body.grade-c {
   @include transform-origin(left, top);
 }
 
+// hide webkit scrollbars
+::-webkit-scrollbar {
+  display:none;
+}
+
 // Scroll bar styles
 .scroll-bar {
   position: absolute;