Is there a way to change the window decoration if firefox becomes the active window
I am on a 2 monitor setup on w10 and I do always work with multiple windows. Alas, the Firefox (and also Thunderbird) windows always look the same if the window is active or not. Thus, I often find myself typing in the wrong window. Is there a way to have a changed frame or background if the Firefox or Thunderbird window becomes the active window?