Interactive Card Details Form using Sass and CSS Grid (mobile/desktop)

I had issues with:

• Responsive Design (really a pain to do that with my spaghetti code) -CVC accepts if you put 3 numbers and one different character -the number input checks if there are 16 numbers of 4 segments of 4 numbers and 3 spaces, but will accept the input if you put in 16 numbers + anything after (still not sure how to use regex to fix this)