By now, pretty much every major operating system under the sun has some variation of the night light feature. If you've never used it before (and somehow still have eyeballs with which to read this), Night Light adds an amber hue to your displays once the sun goes down. The idea is that the color change reduces the amount of blue light reaching your retinas, which is responsible for keeping people up at night, as it tricks the brain into thinking it's still daytime.