Mac: If you're a fan of Night Shift on your iPhone, or F.lux on your Mac, you'll be happy to know that Apple's rolling out an update to macOS today that adds the time-based colour-shifting feature to your Mac.
Windows/Mac/Linux. If you spend your entire day staring into the pit of an eye-burning LCD, free application F.lux may be right up your alley.
Night shift gradually shifts your display colour from blue to an orangeish colour after dark, which supposedly helps you sleep a little better by reducing your exposure to blue light. You can turn Night Shift on in System Preferences > Displays. You can also toggle Night Shift on and off manually by pulling up the Notification Center. The update is available in the Mac App Store right now.