Responsive qr code component using flexbox and media queries

It uses correctly html, the page is accesible, the layout look good on a variety of screens, only in desktop I am not so convinced because it does not look as the requested one. The code is well structured, and the design is good, only using HTML fro structure and CSS for design

I can see in your code you are using media queries but truly you don't need any media queries for this design. I didn't read your whole code now but by looking at your design I can say that you need to add max width to your card component and try to solve it using mobile first approach.