How to get HACS to respect my theme-variables?

Hey guys,

After a long tinker-free break, I am currently trying to adapt to all changes that occurred in the last two years.

One thing, I just cannot wrap my head around is the themeing of HACS. This is how it looks like:

According to the inspector, the background should be defined by one of the following variables in my theme:

  primary-background-color: "hsl(var(--huesat) 16%)"
  background-color: "var(--primary-background-color)"

They do work everywhere else, but HACS - even after changing to a simpler value…

But these variables are crossed out in the inspector and use the default value instead.

I tried checking with other themes, and they do work, even though, they do not use any special variables…

Thank you for any help!!


Edit: screenshot of the crossed-out values below