What method is used for automatic detection of system light/dark mode in linux?

Hi,

I’m with the linuxserver.io team and we publish a docker image for Yaak: https://github.com/linuxserver/docker-yaak

The one question I have is with regards to how the detection is done for system light/dark theme/mode.

In our docker image, we run the app in a containirized minimal linux desktop environment and make the gui available in a browser window via kasmvnc. I tried a few different methods to set the system to use dark mode, including editing gtk settings.ini as well as setting the gtk theme to "Adwaita-dark" but they didn’t seem to work and Yaak defaults to light mode in Automatic. Our desktop environment in the container is very minimal. I would appreciate it if you could point me in the right direction.

Thanks