rj-rayat/MERN1B1-React-Core-Concept-3 ? reverse-engineered prompt

Build me a clean React app using this Vite starter.

I want a simple, polished single page site that feels like a real product landing page, with a header, hero section, a few content sections, and a footer. Make it responsive, easy to read, and nicely styled so it looks good on desktop and mobile. Please keep the code organized with reusable components and sensible state where needed, and use the existing React setup in this project.

If you need to check current React or Vite docs online for anything, go ahead. Also make sure the app runs cleanly with no obvious lint or build issues, and leave me with something I can easily expand later.