Multi-step form challenge

This is my eleventh solution submitted here. This one was more difficult at first than I thought. I had to search a little bit to discover a better way to create it, but when I managed it, all went well. I was able to learn a lot of thing about forms that I didn't understand previously, and I feel that I discovered new and better ways to use CSS and make more responsive websites.

I had to read a few articles to learn some things even though I didn't implement it all in a way that satisfied me, but it was a start. I know that there are many things to improve, and this form is far from complete, but for now, it feels right. I think I can revisit it in the future to make it better.

Do you have any suggestion that you would like to make? Anything is welcome. Anyway, thanks for reading that.