How long have you used it and how is it?

I’m pretty curious about those kinds of distros, and don’t really like how nixos is completely hosted on github (and all the drama that constantly comes from the community, and the bad documentation for many things, …).

However, guix seems such a niche project that I feel like it can’t really be used.

It’s a path inside the container, but not inside /config. You should mount the file like this:

volumes:
  - /path/to/local/theme.css:/jellyfin/jellyfin-web/theme.css

You should put it in Jellyfin web’s root folder (paths are relative to it). In the official container it’s /jellyfin/jellyfin-web.

Then you just @import "theme.css";.

Romero’s Night of the Living Dead is in the public domain as well.

You can find it in the Internet Archive here: https://archive.org/details/night_of_the_living_dead