The colors that you'll actually see will also depend on graphics cards, monitors and graphics settings of each. I have dual monitors, I can drag a window from one monitor to the secondary monitor and there will be a color variation.
However, that said, the template does not use a "safe" color value to take that into consideration. I need to make some technical tweaks and I will add to the list to look at swapping the background shade to windows safe color in hopes that some of you won't get the black anymore. It may take a couple of weeks to get to I'm afraid, there will be images to edit.