CSS Grid, CSS custom variables

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

Pretty happy with the accuracy all things considered. I'd like to do a better a job of taking in all the design details and factor that into my code more deliberately.

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

Was closed to having a "final" product before I noticed the vertical centering. Simple searching provided the approach I went with.

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

I am particularly interested in hearing feedback related to layout and responsiveness, best practices, and tasteful markup.

Also, the rounded corners and the spacing between the QR code borders and the containing element.