This editor needs WebGL 2

The browser could not create a WebGL 2 context. Compose renders this page with Skia on WebGL, so without it the canvas would stay black.

In Chrome, turn on Use graphics acceleration when available in Settings → System. If the GPU is blocklisted, enable chrome://flags/#ignore-gpu-blocklist; on a machine without a usable GPU, enable chrome://flags/#enable-unsafe-swiftshader. Then quit and reopen Chrome.

Check chrome://gpu: WebGL and WebGL2 should not say “Disabled”.