Add support for Freedesktop Color Schemes (Dark Mode)

[AbrarSL]

The Freedesktop Color Scheme Preference is a new cross desktop standard for Dark & Light modes. It is now being widely adopted by major DEs such as GNOME and KDE. Apps are expected to opt in to following this preference. Some information about this preference and how to implement it can be found on GNOME's gitlab.

[AbrarSL]

This is not an electron app? It uses WebKitGTK for the webview and the actual app is written with GTK? Am I mistaken?

Either way regardless of what toolkit the app uses it should be possible to use DBus to check what the current system preference is and adjust the theme entirely on the application side. There is an example in the link I attached that shows how you would possibly do this with something like SDL.

[xeco23]

I did a bit of digging and discovered that this requires a bit of work with GTK3 as opposed to GTK4 which we plan to migrate to. So, I would suggest that we prioritize #239 and this will come automatically.