jatinkumar2197/fitai ? reverse-engineered prompt

Build me a full stack fitness app called FitAI for students. I want it to feel like an AI gym trainer that helps users plan workouts, meals, and habits in one place. It should have a chat assistant for fitness questions, a workout generator based on goals and equipment, a 7 day diet planner with calorie targets, a BMI calculator with simple health feedback, a weekly workout schedule, and a progress dashboard with charts for weight and workout frequency. It should also include a small exercise library with instructions, a water tracker, a habit tracker, and a dark and light mode toggle. Make it responsive and easy to use on phones and laptops.

Use a React frontend and a FastAPI backend, and wire the app to Google Gemini for the AI features. Keep data in local storage so there’s no database needed. If you need current setup details, look up the latest docs online and build it cleanly so it can run locally and be ready for Vercel and Render deployment.