there is actually quite a lot involved in getting this to work right, you'd have to edit all assets... and it's basically like this.
the title bar is three pieces and there are a couple different types of title bars... same thing with the edges... assuming you wanted to edit those, there are all four corners and I believe something like three or four types of corners... plus edges... (that's top and bottom edges) then there is the center piece...
you could throw something together that most others would think is ugly but would work great for you...
as for editing text color... I don't think you can. but I may be wrong.
maybe take a couple screenshots and edit them to show what you want... nothing fancy like... just edit them... and if I have time I could try to throw something together that might work. I hate to see a fellow player suffer and not be able to enjoy such an incredible game.