#193 - this idea turns out to be impossible in the way i originally intended it, because the system of equations is overspecified
there's 6 equations (r, g, b for the first colour; r, g, b for the second colour), but only 4 variables (r, g, b of the shadow colour; shadow opacity)
maybe it could still be done, but i'd have to make one of the colours variable, and then it awkwardly makes the equations underspecified (though this is more workable)
if i were to remove 3 equations, is there a way i can evenly spread the "freedom" afforded to me by the extra variable across 3 colour components, to somehow minimise the amount they change from their previous value?
i wouldn't want to make only red and green entirely free variables for example while blue was still fixed, that would look weird
the ideal outcome would be for the other output colour to shift slightly when you change one of the two output colours