Board Thread:Support Requests - Designing Your Wiki/@comment-25867149-20201017195910/@comment-45117243-20201017222154

Custom site css is prioritized over the default css, but maybe there is an issue with the specificity of the css rules. I can't look into it as I'm currently on a mobile but try body.skin-oasis instead of skin-oasis.

50% 50% will place the top-left corner of the image at the center, wouldn't it?