kareem-diaa/inventory-management-system-project ? reverse-engineered prompt

Build me a simple Python inventory management app that runs in the terminal and lets a small business keep track of products and users.

I want a login and register flow first, then after login show different menus for admin and normal users. Admins should be able to manage users and products, while regular users should mostly work with products. The app should let me add, view, search, update, and delete products, and also handle selling an item so stock goes down correctly. For users, I need the basic create, read, update, and delete actions too, with search by email or ID.

Please store the data in local JSON files so it works without a real database. Add basic validation so bad input does not break the app. Also make a simple inventory report feature that generates an HTML page with CSS styling. Keep the interface clean and easy to use, with clear menu prompts and messages. If you need to check current Python docs or best practices online, go ahead.