Just plain css

Good job!

Some Suggestions:

Remove the padding from your body and add the following to center your card: min-height: 100vh; display: flex; justify-content: center; align-items: center;

Remove everything from your container class except, border-radius, background-color, padding and width. (Change you width size to 320px)

Change your h2 to h1 and have its font-size to 22px. You never want to skip heading levels; always start with h1.

Remove the max-width from your paragraph. You want to use margin/padding to get the style you want.

Keep up the good work.

Goodjob. I had a look at your code and was wondering about your flex properties in your .container class. If you were attempting to centre your container (QR code container) to the centre of the screen, you have to set the flex properties in the parent container. So the container will be centred depending on the height of the parent. So in your .container class remove margin: 0 auto; and the flex properties and put those flex properties in the body and set the height of the body to be 100vh.