Applications suitable for usage at night will have a mode that draws everything in black and red. It's based on the phenomenon that red light still triggers the cones (color-sensitive receptors in our eyes), while not overwhelming the rods (light-sensitive receptors), letting us use illumination (in this case for information display) without ruining adaptation to low light.

(Works best with AMOLED screens, where black = no light.)

See: https://en.wikipedia.org/wiki/Purkinje_effect#Use_of_red_lig....