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

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

type MarginOpts =
    | number
    | [top: number, right: number, bottom: number, left: number]
    | {
        bottom?: number;
        left?: number;
        right?: number;
        top?: number;
    }