Scss, BEM methodology and Vanilla JS for form validation

Hi, are the focus states on the form clear enough? I feel like the button is a bit too subtle, but it's technically the same as the input.

I seem to sometimes get a horizontal scrollbar on smaller screens, but it's not happening consistently so I think it's just a browser issue - or am I missing something?

I also cannot find the thing that HTML validation is picking up on, if someone could have a look and help me out, that would be great :D

Thanks!