Manipulate light so it doesn’t manipulate you. The sun is the best indicator of light! It’s the full spectrum of all light we can and can’t see (the rainbow are the colours we can see) morning and evening sun is higher in Red light, midday sun is higher in the dreaded BLUE light which actually is great for us at midday because our body clock saying it’s midday. Now if you see blue light from phones and monitors after the sun has gone down, you’re telling your body it’s midday!! Blue light blocking screens are handy but they don’t remove all the light. Try natural lights like fire and candles or low level lamps on an evening rather than bright ceiling lights to try keep your body clock in it’s natural rhythm to have a good nights sleep.