How to create a theme which only administrators can use?

I solved all my problems by modifying my moderators roles via CSS. It’s a very complex situation and the only real solution was this. I already tried category moderation and it was not viable for my forum, it was not interesting for the demand. The only way that solved my problems was the modifications via CSS. As Discourse leaves the same moderator options to admin, this was the only solution. But now I just need a way for me to be able to use a theme that doesn’t have CSS modifications. So I don’t have to turn it off every time I use it.