Design a fullstack web application when the prompt explicitly emphasizes the frontend. Given a 2–3 page requirements document plus a demo (screenshots and an animation), outline: ( 1) Frontend architecture: framework choice, routing, component decomposition, state management, data fetching strategy (client/server/rendering model), error/loading states, accessibility, performance (code-splitting, memoization, virtualization), and testing. ( 2) API contract: define REST or GraphQL endpoints, request/response schemas, pagination, auth/session, and rate limiting; specify how the UI maps to these contracts. ( 3) Backend design: service boundaries, data model and storage, caching, background jobs, idempotency, observability, and scalability. ( 4) Deployment: CI/CD, environment config, canary/rollback. ( 5) Process: how you validate behavior against the demo, prioritize scope under time pressure, and collaborate on ambiguous requirements. Provide one critical user flow and describe the end-to-end sequence of UI actions and API calls.