I’d love to know this too. From the few video reviews the colours look static enough, but pictures around FW website show you anything from red/orange through to blue/green, so I suggest they must be able to change colour somehow, otherwise you’ll be playing roulette whether or not they match with your system and your taste.
I thought they could be thermal based, but this doesn’t seem right since I’d imagine you’d see handling marks in pictures, and it would probably be less than flattering if you were laying your hands across it for a while.