Is there a way for me to change the color of the active window (titlebar and such) because quite frankly the default "inactive" and "active" differentiation between them is very subtle that I have no idea which window is currently active and I often find myself typing away only to find a little while that it was in a wrong window.
I'm using GNOME if that matters.
It's not exactly what you've asked for, but nevertheless to distinguish between focussed and background windows you may use blur effect for background windows. To achieve that you may use a GNOME shell extension called Windows Blur Effects. You can change the desaturation, brightness and contrast of background windows using this extension.
(screenshot source: extension's homepage at extensions.gnome.org)
