The threejs scene in the docs is only for explaining the setup; it doesn't have a raytracer to render shadows accurately. The reference renders for the CSS were done in Blender. See https://kikkupico.github.io/ambientcss/ambient-css/grounded#... for examples.
Indeed. Those are even more off. It's like they haven't actually looked at what the AI produced - or the agent is also the one writing the replies here.