CSS variables

HTML:

• Every webpage needs a <main> that wraps all of the content, except for <header> and footer>. This is vital for accessibility, as it helps screen readers identify a page's "main" section. Wrap the card in a <main>.

• The alt text must also say where it leads(the frontendmentor website). A good alt text would be "QR code leading to the Frontend Mentor website."

• I would change the heading to a <h2> - a page should only have one <h1>, reserved for the main heading. As this is a card heading, it would likely not be the main heading on a page with several components.

• .attribution should be a <footer>, and you should use <p> for the text inside.

CSS:

• Including a CSS Reset at the top is good practice.

• I would recommend adding 1rem of padding on the body, to ensure the card doesn't touch the edges on small screens.

• It's not common to set styles on html. And you need neither of those properties. Read more about why you should not set font-size: 62.5%.

• On the body, change height to min-height - this way, the content will not get cut off if it grows beneath the viewport.

• Remove the width and height on the card. We rarely want to give a component a fixed size, as we want it to grow and shrink according to the screen size.

• We do want to limit the width of the card, so it doesn't get too wide on larger screens. Give the card a max-width of around 20rem to solve this issue.

• letter-spacing must not be in px. You can use em, where 1em equals the element's font size.

• Since all of the text should be centered, you only need to set text-align: center on the body, and remove it elsewhere. The children will inherit the value.

• On the image, add display: block and change width to max-width: 100% - the max-width prevents it from overflowing its container. Without this, an image would overflow if its intrinsic size is wider than the container. max-width: 100% makes the image shrink to fit inside its container.

• On .attribution, change font-size from px to rem.