Mobile first approach using React and moment.js

Hi there,

This is the sort of challenge that looks easy but it's not.

I'm not 100% satisfied with my solution but it does work, I ended up using a custom React Hook for the input fields and the trickiest part was not the part about working with the date, it was the part about setting error messages. I validate the inputs on blur and check if the given date is valid on button click. I used moment.js for handling the difference of dates.

Feel free to leave any criticism.

Florian