Product preview card component solution

I started using the rem unit in this project and it went smoothly while I was working on the mobile design. But when I moved on to the desktop design, I couldn't make it responsive until I switched to vw. I also had trouble with the image, as it wouldn't fill its half of the container until I set a smaller min-width, and with the positioning of the button, which starts moving to the bottom of the container when I make my browser's window small enough. I still don't understand why I had those issues and I would be thankful if someone could explain them to me.