Creating custom Fcolor library

Hey all,

What would be the best way to build a library of custom colors to call up in the fColor commands that could be referenced throughout the game?

I have an in-progress UI style guide to adhere to, and in the likely event of the colors being revised, I was hoping there was a clean way to approach globally revising the hex values at the root of the color library, rather than manually revising the colors of each individual widget.

Thanks