The demo used block layout to stack controls and a focus pseudo-class for keyboard feedback. The starter already has the associated label, stacked controls, and a responsive-width email input; do not change the HTML. Add just the spacing and focus feedback in style.css.
margin-bottom: .75rem to input to give the button breathing room.outline: 3px solid #f4a261 on input:focus so keyboard users can see the focused field.Checkpoint: Preview shows a gap below the email box, and tabbing to the input gives it an orange outline. This is a visual form only; submitting does not send data.
Keep the stylesheet linked from the document head.
Change one declaration at a time, then use Run Preview to inspect the result.