Ecommerce Product Page with React

This is my first project with React. Any constructive criticism is appreciated!

There was one element that I couldn't figure out in the mobile view. When you open the cart, I wanted it to align perfectly over the image and spread out to the width of the image (as seen in the design). I couldn't work out how to do this on top of the code I'd already written. Does anyone have any pointers? I was able to hack it by setting the position to absolute and moving the div around, but it wasn't exactly centered. What are the best practises for this?