Color based font/"color" processing program

I would like a program where I can assign colors to letters of the alphabet/keyboard and be able to type out sentences in blocks of colors. I would also like to assign functions to bold (a darker shade of the color), italic ( a blending of adjacent colors) and perhaps shift or alt could reveal the letters assigned to the color. I suppose what I am really looking for is a color based font family that can work in MS word. I use Mac so I need this to work in OSX.