We are trying to automate an ecomm website which uses JOOMLA for content management.

The task for our automation team is to assess the manual test pain point after every release which is the CSS rendering and say if it can be automated.

I have tried to explore and see a lot of tools which operate on the screenshot comparison method. Others validate the css stylesheet, but even a valid css should render incorrectly based on browser, cache clear, etc

Can any part of it be done using tools like Selenium or Eggplant?

Has anyone tried doing this and come up with a viable solution?