Bumping this thread, but throwing some votes to kind to request this more as an accessibility option than anything else.
Explaining a bit better, I've had keratoconus since I started playing this game, but as the disease progressed and I underwent a surgery around two years ago to implant intacs to my right eye the glare issues in my vision got worse and now I see halos around every bright object in a dark background unless I close my right eye, this makes the game very annoying to play without using the magnifier function in Windows to invert colors making it effectively a white BG with black circles. But of course, this inverts every color in everything not only in osu and is a makeshift solution that works but at the expense of making the game uglier and browsing other applications while playing super weird.
So yeah, I would really appreciate if I could just change the dim color and customize the circle and cursor colors through the skin without having to invert the colors of everything on my screen.