Responsive newsletter signup form with real time form validation

What are you most proud of, and what would you do differently next time?

This is my 1st mobile-first workflow project. Now I understand how to choose design workflows! I think flexbox works well with mobile-first workflow. I ended writing very less CSS.

What challenges did you encounter, and how did you overcome them?

Writing media query's was quite challenging because I was used to write CSS from desktop to mobile workflow.

What specific areas of your project would you like help with?

I want to write modular CSS code by using @container and :has(). I want to use form validation API's and modules in my next complex form project. Please recommend me complex form validation projects.