Add a class to already "read" Articles (AUP Rule Read Article By Categories)

I'm planning to buy the "AUP Rule Read Article By Categories" if it is possible to add a class to links that point to an article that the user has already earnt points once.

The idea is to show what articles the user has already read (for example, online course progression) by displaying a "complete/checkmark" next to articles in a menu that the user has already visited. Currently, I can do something like that with a:visited, but that method doesn't "sync" with different devices.

I think this could be possible with AUP. What do you think?