Fan Casting Orange/Blue Contrast in Sort by Tropes

While other pairs of complementary colors are associated with specific concepts, fiery orange and cool blue are strongly associated with opposing concepts — fire and ice, earth and sky, land and sea, dawn and dusk, invested humanism vs. elegant indifference, good old fashioned explosions vs. futuristic science stuff (and the obligatory Good Colors, Evil Colors contrast). It's a trope because it's used on purpose, and it does something. Especially in theater, orange and blue are sometimes referred to as amber and teal in this context.