Compared to how many provide styles for the :hover, rarely do people provide style for the :visited CSS pseudo-class, including me.
Interestingly, while you can go as crazy as you want for the :hover, there are some limitations for the :visited. You can only change some "basic" properties, like the color of the text or background.
Because of privacy reasons.
I came across a site where they styled the visited links, and I was super grateful they did.
It's an archive site for an old radio show where they just dumped the links to the individual episodes (MP3 files). With the :focus style in place, I don't even have to keep track of the episodes I listened to. I can tell which ones I opened and where I left off.
(I'm always listening to this show from my phone.)