Color of hyperlinks do not change even after clicking them

The links have color red. How do I make them change once a user clicks/visits those links?

Thanks

Use a:visited selector

I did not understand this. Can you please explain in simple words?
Sorry for trouble

Try this: https://www.w3schools.com/cssref/sel_visited.asp

You’ll have to override the :visited for your links.

Thanks a lot. It worked