seth18dm/nexa-store ? reverse-engineered prompt

Build me a simple but polished online store called NEXA STORE.

I want a full shopping experience where people can browse products, view product details, add items to a cart, and go through a basic checkout flow. Please include a clean homepage, product listing, search or filtering if it fits naturally, and a cart that updates properly. Make it feel modern and easy to use on both desktop and mobile.

Use the existing project structure and set it up as a working MERN style app with a frontend and backend. If you need to check current docs or best practices while wiring things up, go ahead and look them up online. Keep the design neat and responsive, and make sure the main flows actually work end to end with sensible sample data if needed.