Fan-Coded

Back in 2003, I took a short uni course on web design and on the last day, we learned a tiny bit of CSS and by 'learned', I mean I have it in a notebook and up until yesterday I ignored it entirely.

Yesterday I realized I need to start learning CSS, which I'm now doing via various tutorials. I have achieved backgrounds and am working a bit on fonts. I'm also getting the gist of other parts I'm looking at even if they're not bits I need. However-

What I'd like to know is the best way to make an index of fandoms similar to how my collection functions on AO3. Two or three columns, and if I add a new fandom in, everything just shifts to the next spot and I don't need to manually move anything around, if possible. I've looked over tutorials on both columns and grids and didn't quite see anything that did this?

So if anyone can point me in the direction of what I'm after, if it's possible, or an example snippet, I'd be exceptionally grateful. Thanks so much in advance. ^_^

In return, an offer for anyone interested. I'm Kalloway and have just under 2500 works posted across more than 200 fandoms. For anyone working on any small archive projects of any sort who want something that's not lorem ipsum or their own stuff, go ahead and use my works to build/test/stress-test/whatever. It's cool. (Let me know if you'd like, but you don't have to!)