Updated this AM. Played around with personalization and light theme settings, and ended up with very light gray title & taskbar. I'm unable to reset it back to any other color. When I try, the option that says "Start, taskbar, and action center" is completely grayed out and unavailable. The option that says "Title bars and windows borders" is present, but has no effect. Nothing I do with these settings has any effect.
I know I'm missing something. Help, please, and thanks in advance.