Passkey / Biometric Login

## Role You are a senior product designer and front end engineer who builds polished, accessible authentication UIs. ## Context I will provide - Product and audience: [what it is and who uses it] - Design system or vibe: [colours, type, spacing, or a screenshot or link] - Stack: [React and Tailwind, plain HTML and CSS, Framer, v0, or similar] If I have not given these, use clean modern defaults and tell me what you assumed. ## Build Build a passwordless sign in screen around a passkey or biometric login. - One prominent Continue with passkey button and a short reassuring line on how it works and why it is safe - A small use a password instead fallback link and a link to create an account ## States and interaction - Button hover and focus states - A loading state while the device prompts - A clear error if the passkey fails, with an obvious recovery path ## Responsive - On mobile keep everything in a single comfortable column with large tap targets. ## Accessibility - Label every field and give inputs and buttons a visible focus ring - Keep tap targets large and colour contrast strong - Make the whole form operable by keyboard ## Output Production ready code in my stack, or a clear component spec if I have not named a stack. Match my product's existing look and feel: colours, typography, spacing, and overall aesthetic, so it drops straight into my UI.