This demo's UI renders with WebGL2 (and it trains on WebGPU), both of which your browser has disabled or blocklisted.
If you're viewing over SSH X-forwarding or a headless / VM session, open it from Chrome/Edge on a machine with a real GPU — e.g. port-forward the server and use your local browser. (This demo runs on the viewing machine's GPU, not the server's.)
Or force WebGL: chrome://flags → "Override software rendering list", or launch Chrome with --ignore-gpu-blocklist --enable-unsafe-swiftshader (note: software WebGPU is not available, so training still needs a real WebGPU device).