I hope I can get the images into this post correctly and that it's OK to link in one from the documentation...
first is the image from the 03. Creating Your First Scene tutorial on the colors in the Base Colours dialog - note the blue outline which indicates the settings being discussed:
now here's a screenshot of the same dialog from my Mac:
I had been wondering why there was only a single numeric field for a color (which ends up being grey when one uses it), and a slider (which does have the nice effect of darkening colors when a color has been chosen via the swatch), but really, it'd be a lot more sensible if it had the three fields (which I presume are red, green, and blue amounts, yes?) just like on the Windows version.
of course it may all be moot in the final UI, anyway.
thanks for your attention!