Flux

f.lux is a popular screen color temperature adjustment utility that automatically warms your display colors based on the time of day and your location. It reduces blue light exposure in the evening and night hours to help reduce eye strain and improve sleep quality. The app runs quietly in the background and gradually shifts your screen from cooler daytime colors to warmer, amber-tinted colors as the sun sets. It's widely used by people who spend long hours at their computers and want to reduce the impact of blue light on their circadian rhythm.