How to reset CSS to default?

[Fpo72]

Hi,

I'm sure this is a super  basic question, but I can't find a solution right now.

I did not use Jellyfin for a while, but now I wanted to take a look at it again.

I was using a custom CSS, which is obviously broken.

   

I can see the default theme for a split second, but then it changes to the broken custom one.

How do I reset the CSS, so that I can login again?

Thanks for helping me out!