vignette
Vignette effect. Darkens or tints the screen edges; can mimic some Arcaea anomaly effects.

Parameters
color(color, default black [r, g, b, a]): Edge color.extend(float, default0.25, range 0–1): How far the edge extends; larger = more darkened area.radius(float, default15.0): Size of the central bright area; smaller = larger affected area.