Interactive Card Details Form

My first junior-level project! It took me a while to figure out the JavaScript form validation, but I learnt a lot along the way.

I feel like I could have removed some of the duplication in my JavaScript validation code, but I decided against it as there were some things that varied for each input that needed to be validated (updating the values displayed on the card, allowing different ranges of values, providing slightly different error messages, etc.). Would love to hear your input on my JS setup.