Glad you enjoyed it! Three points turn is one of the core mechanics:) It takes time to develop some sort of vision that allows to play without hints, so you're doing good!
There's no particular reference, I just love hexagons and tried to adapt celtic patterns to hex grid.
There are several variations for the same edge/connection type, it makes the whole pattern to feel more or less dense and tangled. It's playing with perception and changes visual complexity without changing actual complexity.
What do you mean about different gradients? Like every connectivity variation to have its own color? So you know how many sides are connected from color?