Interactive card details form with vanilla JS

I used vanilla JS for this project to see if I could still use it. The funny thing is that I also decided to use SCSS for this project and didn't even realize I was writing normal CSS in a SCSS file until the very end lol. I'm just gonna leave it this way to remind my future self that I did this. I tried handling every possible errors I could think of which took me quite a while to finish but it was definitely worth it. Any kind of feedback or suggestion would be much appreciated. Thanks in advance and Happy Coding!