Authentication pages: sign in, sign up, forgot password

Visitors move between screens without a page reload, and the e-mail address already typed follows them. Sign in offers a password reveal, Remember me and a warning when Caps Lock is on. Sign up shows three criteria that tick as you type and checks that the confirmation matches. Forgot password always gives the same answer, whether the account exists or not, so it never reveals who is registered. Errors appear under each field on submit and focus moves to the first field to fix; fields carry the right autocomplete attributes for password managers. Accessibility: everything works with the keyboard, each message is tied to its field through aria-describedby and aria-invalid, the reveal button is a toggle (aria-pressed), criteria and Caps Lock are announced by live regions, focus moves to the heading of each new screen, contrast exceeds 4.5:1 in light and dark modes and the animation stops with prefers-reduced-motion. Without JavaScript, the three forms stay usable with browser validation. Plug in your authentication service: atr:submit event in HTML, onSubmit prop in React.