Board Thread:Support Requests - Getting Technical/@comment-4723271-20170828013120

How do I change a wiki's background using CSS rather than the theme designer?

Backstory (you're probably not interested or it isnt necessary, but I'm gonna add it anyways) -  I recently updated the background on this wiki. The users like it but one user in particular is having issues with it. The background is showing up much smaller on her screen than everyone else's. I tried redoing the background but that isn't going to work without cutting too much out. So I figured I'd just add a bigger background that would fit her screen to her personal CSS. I just don't know the coding. 