Board Thread:Support Requests - Getting Technical/@comment-253018-20191102224144/@comment-9605025-20191103015302

When you say you tried adding themes, what was it you were doing? Do you have particular pages you tried this on that we can look at?

Some wikis put their infobox themes in a separate CSS file and import it using the main CSS. That could be why you can't find it in their Wikia.css or Common.css.