I completed this challenge with the most basic vanilla CSS and JS. I think that my CSS could be better structured and therefore more concise. I hope this is something that I will be able to achieve when I start using CSS frameworks.
I found JS really difficult - at first, I tried it with named function and loops, but could not get it to work. So I went back to the very basics and ended up with the ugly code as it is right now. I shall come back to it and refactor it at some point.
I would appreciate any pointers about refactoring this JS code.