I'm Back! Made with CSS Grid and JavaScript vanilla

I'm back by popular demand. Or maybe not. Well, a couple of months of inactivity. A lot of changes in my life, but now we're ready to keep practicing.

I had this challenge almost ready when I took my unsolicited break. The most difficult still is posicionate the background in the right place. I don't think it quite match up perfectly, but it looks good, at least. If you can recommend me a better solution I'll be thankful and open to hear you.

I worked with grid for the page structure. For the JavaScript code, I created a helper function to check if the email enter by the user is valid, I tried multiple regex expression until I found out the one that satisfied the result I wanted to obtain. Then, I added styles conditionally using ternary operator because I didn't want to repeat myself too much. Plus: I added an indicator when the email is send successfully.

I hope you can review my code and show me improvements that I can make to my code. I'm all ears!