Order Summary

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 everything in a <main> element.

• Replace the ids with classes. This article explains the use cases for the id attribute.

• I would change the "Order Summary" 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.

• "Change" would likely navigate somewhere, hence it should be a link, not a button.

• "$59.99/year" is a <p>, not a heading.

CSS:

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

• I like to add 1rem of padding on the body, to ensure the component doesn't touch the edges on small screens.

• Remove display: block on .container - it is a <div> which by default is a block element.

• Remove the margin on .container.

• To center the card horizontally and vertically, use Flexbox on the body:

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

• Remove all widths in px.

• Add width: 100% on the "Proceed" button, and give it some margin so it doesn't stretch across the whole card:margin-inline: 30px;.

• Add a max-width of around 40rem on the card, to prevent it from getting too wide on larger screens.

• Instead of border: none, it is recommended to use border: transparent.

• font-size must never be in px. This is a big accessibility issue, as it prevents the font size from scaling with the user's default setting in the browser. Use rem instead.

• I would give the <button> inside .plan a class, and select it in CSS via that class, instead of using plan button, which increases specificity. I would also remove margin-left and replace it with margin-left: auto; - this pushes it to the very right.