You can make them white by changing the board line colors if you really want to.
But I really can’t imagine the font color mattering at all.
Even when you ask some players, e.g.
, some of these blurry shapes are tagged in my mind as “Black”, others are tagged as “White”, but it can be hard to keep track of which intersection is black or white. My thoughts sound like this: "Black, White, Black, (…) Now this blurry shape consists of 3 black stones, and this other one of 4 white stones.
they’re not necessarily even picturing a coloured stone necessarily.
I would be very similar and this would be how I imagine things, so the font colour could be purple or bright red or anything and it shouldn’t matter. For me it only matters to be able to read the numbers, and maybe if it was distracting in some way like it was flashing or there was some strange optical illusion with the colour and the lines then maybe.