I need a lean, front-end MVP built in React that lets patients do three things with ease: keep track of their own medical records, book appointments, and handle billing or invoicing. The goal is to demo these flows end-to-end so stakeholders can validate usability before we invest in a full-scale build. Core scope • Patient records: create, view, update, and delete basic demographics, visit summaries, and file attachments (use local or mocked API storage—no HIPAA data involved at this stage). • Appointment scheduling: calendar view with available slots, confirmation screen, and simple reschedule / cancel actions. • Billing & invoicing: list of outstanding invoices, card or PayPal mock checkout, and downloadable PDF receipt. Tech & workflow React (hooks, functional components, react-router) is a must; feel free to bring in Redux Toolkit or Context API for state, plus Material UI or Tailwind for styling if you prefer. A lightweight JSON server or mocked REST layer is fine for data—no complex back-end work expected. Please push code to a Git repo and include a brief README with setup commands (npm install / npm start) so I can spin it up locally. Acceptance check 1. All three modules are reachable from a single-page application with clean routing. 2. Actions persist across page refreshes (localStorage or your chosen mock API). 3. UI is responsive on desktop, tablet, and mobile breakpoints. 4. Code is lint-clean and builds successfully with create-react-app or Vite. If you’ve shipped similar healthcare or booking apps, include a link in your bid. I’m ready to review prototypes right away and will give fast feedback so we can iterate quickly.