Your system asks for reduced motion, so VFX-JS draws nothing. Demos on this site show plain HTML.

import type { EffectAttributeDescriptor } from "@vfx-js/core";

type EffectAttributeDescriptor = EffectAttributeTypedArray | {
    data: EffectAttributeTypedArray;
    itemSize: 1 | 2 | 3 | 4;
    normalized?: boolean;
    perInstance?: boolean;
}