Custom background from local files

[toastoaster]

Hello,

I saw this subreddit: https://www.reddit.com/r/jellyfin/commen...ocal_file/
but it does not work exactly like this in my case.

My setup: Jellyfin as a docker image on a Synology NAS
I would like to use a picture from the local filesystem but I do not know where I can start with the relative path.
When I use:

Code:

#loginPage {
  background-image: x;
  background-size: cover;
}

It does not work with either of the following replacements for x:

Code:

url('config/data/login_background.jpg')
'config/data/login_background.jpg'
'../../config/data/login_background.jpg'

Thanks in advance!