RiyazAhamed
Yes, because the structure and class names have changed in the new platform.
But the new platform provided a much better hold of CSS classes. So it becomes easier to customize with custom CSS code.
Also, whenever we get some suggestions from the community on "how to do this with custom CSS" we check if that's possible, if not, we add the custom CSS class name to that particular block so that it can be customized easily.
