Hole Background

The tunnel is decoration: the canvas and the vignette are aria-hidden and ignore the pointer, and children render above them in their own layer with their roles, focus order and hit areas intact. The vanishing point following the pointer is an optional flourish tracked on the root without capturing events, so nothing depends on it. The vignette fades toward the page background, which helps text laid over the edges. The loop pauses off-screen and in hidden tabs; under reduced motion (or a --motion-scale near zero) it draws one still frame of the tunnel, centred, with particles caught mid-fall, and ignores the pointer.