As a rule the displays of notebooks and computer monitors are set so as to be easy to read in the daytime, but when it's darker, these settings aren't always optimal for the user. One solution is the freeware programme F.Lux, which automatically adjusts the colour tone of the display to match the time of day. By day, the usual bright colours dominate. But by night, warmer, darker colours take over.
These are kinder for the eyes and it's also good for the sleep pattern to avoid blue light in the evening. F.lux is available for Windows, Macs and Linux computers.