Board Thread:Support Requests - Designing Your Wiki/@comment-31305254-20180802214947/@comment-1915363-20180803000725

I think you're looking for this page: https://novilar.wikia.com/wiki/MediaWiki:Wikia.css

As for your other problems, well, you basically can't edit the preset CSS styling of the Wikia theme. Best you could do is to overwrite them with an inline style, or use an !important override, and even then, there's nothing you could do about the headers, other than getting a higher resolution monitor.

Perhaps I can get a better insight if you give me a screenshot on the issue.