Site key for this demo: sitekey_402t_demo. After verifying, the form gets a hidden
captchaToken. Your backend should call POST /api/siteverify with the secret key
(never in the browser).
The widget follows prefers-color-scheme by default. Use
data-theme="light" or data-theme="dark" on the container to force a look.
Dark page
Light page (forced dark widget)