Interactive card details form - React.js , CSS Grid

This was my first "real" project with React! Getting the controlled inputs and form validation to work was relatively straightforward, but I still have a few questions:

1. I had a hard time understanding exactly how to implement the desktop design and what UI elements should be responsive. I'm curious: how did you guys approach adding responsiveness to this design?

2. Why is my live site getting blocked by Google Chrome and detected as a phishing attack? Has anyone else faced this issue? I'm also getting an error message that says "Automatic credit card filling is disabled because this form does not use a secure connection" whenever I type into the form inputs, but I'm hosting my site on Vercel, and (I believe) HTTPS is enabled. How can I fix this?

Thanks!