QR code using CSS

Hello As a newbie and this being my first project a lot of things were hard to do. I found it difficult to organize my divs as well as define their dimensions as I wanted, I tried working on anther project it was the same which is a clear indication that I need to learn more on how to use margins, paddings, width and height. Every help would be appreciated. I am unsure of how to find appropriate colors, write well structured html codes and managing the dimensions of images and divs. I am open to learning new practices and would appreciate your review on my overall work and things I could do better. I'd also appreciate resources tagged with the review pointing me to good resources that would be helpful in improving my html/css. Looking forward to your reviews Thank you. Best regards, Success