I'm not wide awake before I go to sleep.
It's not possible to do design work with a blue light filter
Honestly, if I was to buy a new computer, this is the first thing I would download.
Although Apple and Google have integrated blue light filters into their operating systems, they still haven't matched the capabilities that f.lux offers. f.lux gives you more control over the filter strength and once setup, you don't need to touch.