IOrlandoni/Credit-Card-Generator ? reverse-engineered prompt

Build me a simple credit card generator and checker that can make fake card numbers for testing and also tell me if a number passes the Luhn check.

I want to be able to enter a BIN or starting digits, choose a card type like JCB or similar, and generate a valid looking test number with a fake expiration date and CVV. It should also let me paste in a card number and see if it is valid or not, with a clear result message.

Please keep it easy to use, with a clean page and a straightforward form. If it makes sense, show a few generated examples and explain briefly why a number is valid or invalid. Look up current docs online if you need to, but keep the project lightweight and focused on this one purpose.