snehadasgupta1675-bit/cognevance_ecommerce_platform- ? reverse-engineered prompt

Build me a full stack e commerce site for a small online store. It should have a clean responsive React frontend and a Node, Express, MongoDB backend.

I want users to browse products, see product details, add items to a shopping cart, update quantities, and remove items easily. Include order management so a user can place an order and then view their past orders and order history. Also add a simple demo payment flow so checkout feels complete, but it does not need to process real payments.

Please make the app feel polished and easy to use on both desktop and mobile. Set it up so the backend and frontend can run separately, and keep the code organized so it is easy to expand later. If you need current setup details or best practices, look up the latest docs online and use what fits best.