QR code component

What are you most proud of, and what would you do differently next time?

I am proud of the look. I think its close to the design... how do you check if you're close and don't forget something like a little bit different color?

What challenges did you encounter, and how did you overcome them?

What is the best way of centering this element? I used flexbox on the body, give it a hight of 100vh and center it. I was also thinking about centering with:
top: 50%; left: 50%; transform: translate(-50%, -50%);

Would you use a main tag?

What specific areas of your project would you like help with?

Is there a better / easier way of doing this challenge? And how can I find out about it?