thanks for the information, a query, implementing gtk3 is easy just like gtk2
Yes, apart from those bit of GTK3 that don't work in Lazarus, and, sadly, thats quite a lot.
Grab yourself a Linux ISO and install Linux, then you will be able to do, easily, what you want. Join us, do not be afraid.....
Hmm, another approach would be to use QT5, there is a tool on Linux, and, guessing probably Windows too that allows you pre-define pretty much all of the colours for any Qt5 app. I, guessing again, think you should be able to install the Qt5 libraries on Windows.
Davo
Davo