newsletter signup with success message HTML CSS and JS

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

I think i got the design near pixel perfect, it looks really nice

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

It was my first time using forms, i still have a lot of questions. I was considering to just check if the user uses an @ in the input. But then i decided to use regex instead.

I didn't knew how to show the success message and considered to put it in a separate html file. But in that case it will be difficult to share data between them, so i just hid the form and message as needed.

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

I want to know if the way i did it is correct or there is another optimal way of doing it. in terms of handling the form submit and all that. It will be greatly appreciated.