Using a Linux distro with Gnome desktop and want to run a specific app in dark mode, without having to change your entire system’s theme setting?
Here you go:
$ GTK_THEME=Adwaita:dark <app-name>
You can replace
Adwaita:dark with any other available theme. To find your available themes you can inspect your themes folder:
$ ls /usr/share/themes/ Adwaita Emacs Pop-dark Pop-light-slim Pop-slim-light Adwaita-dark HighContrast Pop-dark-slim Pop-slim Raleigh Default Pop Pop-light Pop-slim-dark