Sorry for the late reply... I haven't seen a tutorial to do this, I've just been trying different techniques until I was able to achieve it.
Basically what I did was apply a tint effect to the layers where I have all the graphic elements and I changed the RGB value based on the colors of a gradient that I made according to the colors I needed and also made a layer (on top) with a multiply effect that contains a dark blue rectangle (the size of the visible area) whose opacity gradually changes to be darker at night and transparent at day.
It's a bit more complex than it sounds but basically that's the way I did it.