Don't worry about them, just secure the rabbit, get a claw and push the fur away, find the vein and cut a bit above it. Generally if you don't cut past the fur you don't cut the quick, 6 of my rabbits have dark nails and I can't see their quicks (vein in the nail), so I just cut them to the length of the fur and I can't say I've ever had a rabbits nail bleed