sih3110/MERN-Authentication-System ? reverse-engineered prompt

Build me a simple MERN authentication system with a frontend and backend.

I want users to be able to sign up, log in, and log out, with their session handled safely so they stay logged in when they come back. Make the app feel clean and modern, with a straightforward home page, auth pages, and basic protected area that only signed in users can see.

Use a React client and a Node and Express server with MongoDB for storing user accounts. Add form validation, helpful error messages, and good handling for things like duplicate emails or wrong passwords. If it makes sense, use current best practices for auth and look up the latest docs online if you need to.

Please set up the project so it runs easily from the root, and include the backend and frontend code needed to make the whole flow work end to end.