Visited links

Hi guys, thank you very much for this great plugin!
My homepage is a text-only page and I like to have a different style for the already opened modal links. In this way people know which link they have already see or not. Do you think it is possible?
I mean, on non-modal links the :visited property works fine, but probably the fact that content is shown inside the same window can’t be read as visited.
Do you see any solution?
Thank you very much
Marco