QR code component using HTML and CSS

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

I'm coming back from a long break and this was a refreshment, so I guess nothing much to be proud of. However, I think was able to write a relatively well-structured, semantic HTML and clean CSS :)

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

Forgetting some of CSS's properties and its usage, and got through that with little search in MDN docs.

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

I give great importance to writing clean code. If you have any feedback on this area, I'd appreciate it.