Tip calc with React, Typescript, Sass

Decided to try react+ts. It was pretty hard for me. Not sure whether hooks are supposed to be used like that. I'm just starting to learn them and I'm not sure I understand them. Also encountered strange behavior of input type="number" input fields with react. I should probably have instead used inputs of type="text" and do all validations by react. I don't have any specific questions(or rather there are too many of them), but I'm not against any suggestions or feedback! :)

Also there is an Easter Egg 🥚🐣 Type 123456 to the bill and press reset :)