Board Thread:Support Requests - Getting Technical/@comment-25013146-20140606102908/@comment-856287-20140607175213

Asking for the answer is a good way to learn! I recommend it. ...but I can understand not wanting to wait for a response.

.imgUnder and .imgOver are just names I made up when I wrote this (because one image would be 'under' and one would be 'over'). I could have used .frog and .justice if I wanted. They're just arbitrary names, so Googling won't turn up much. If if happens to be a popular snippet of CSS, then searching the class selectors might turn up some good results, but otherwise, no, it's just whatever the person wanted to call it. For example, if you searched around for the selector ".WikiaPage" you might find something useful because lot's of people will have posted here-and-there about styling an element with the class "WikiaPage" ;)

For other types of CSS selectors besides classes (and IDs), the names are fixed, like HTML elements. Then there are also psuedo-elements like :hover :active ::before ::after etc. Those are all fixed as well.

I kind of explained how to work with CSS on Wikia here, though I probably could have done a better job of it. Still, you might find that brief post illuminating.

The best strategy I can offer is to have a specific outcome for your code in mind, and then search around and ask for how to do that specific thing. Once you've tried out several things, the code will just start to make sense to you and you'll be writing your own.