f.lux warms up your screen at night to help you relax and wind down before bed. Created in 2008 to help screens look more like a book, f.lux is now informed by science in sleep and circadian biology to help you adjust your body's sense of night and day.

This version includes a "bedtime mode" which allows you to see the lowest light levels before bed, and an automatic analysis of how light affects your body at different times. And if you have smart lighting at home, you can make your lights match your screen.