Beginner QR Card

HTML:

• You need a <main>, this is important for accessibility. The main> can also be the card. I would remove all divs, as they are not needed. .attribution should be a <footer>, and its text must be wrapped in a <p>.

CSS:

• It's good practice to include a CSS Reset at the top.

• Font-size must never be in px. Use rem instead.

• Since all of the text is centered, you only need to set text-align: center on the body.

• Remove the fixed width. You rarely want to set fixed dimensions, as this easily creates issues with responsiveness.

• Add max-width: 20rem on the card, so it doesn't get too wide on larger screens.

• Instead of using margin on the card, you can use Flexbox on the body:

display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
min-height: 100vh;

• On the image, remove height, it is not needed. Replace width with max-width: 100%, and add display: block.