Responsive Product Preview using HTML and CSS

On my first challenge, I only used <divs> in my HTML while in this challenge I tried using semantics such as <main>, <section>, etc. although I believe I could have used a different semantic for <section>?

Also, I tried doing the mobile-first workflow unfortunately I was unable to stick to it and ended up doing the desktop version first again like how I did on my first challenge. Does anyone have any tips on their workflow regarding this?