Board Thread:Support Requests - Designing Your Wiki/@comment-25714421-20170730144102/@comment-35808945-20180607140955

You can try but I believe MediaWiki (or, at least Wikia) has some bug where in-line use of "background-image" is ignored. So, I don't think it will work. As for transferring the text shadow, there is no "import" capability. You just have to add the relevant CSS to MediaWiki