Numbers can be entered in several ways.
As HTML color codes, such as "#FFFFFF" (white). Number sign optional.
Standard numbers, like "255,255,255" (white, again). Use commas, spaces, or pipes.
Do NOT mix and match.
This is intended for "tinting" HTML colors, and it won't be very useful for other things.
If you don't understand all this, just click "Choose" for my handy dandy color picker.