Newsletter sign-up with success message using Grid

I managed to keep the entire form post interaction contained within the same page. I normally use PHP for form submissions (POST method combined with the PHP Super-Globals).

I think you can use Fetch in Javascript for the POST method but I've didn't think that was necessary in this case and the form GET method is best avoided for user data.

Used some data attributes in various elements to show/hide various sections. and took advantage of this as you can format with CSS using an attribute selector .something[attrib="value"]

The transition between break points is a little jarring but It's about practice not perfection.

You decide.