Padding box-sizing — Code Challenge

How it works

• Border-box sizing includes padding and border in the declared width. It helps a full-width card fit its container without arithmetic adjustments.
• A box includes content, padding, border, and margin. Use the developer-tools box diagram to see which layer creates a gap.
• Prefer logical properties such as padding-inline when a layout should adapt to different writing directions.

Your task

Use the HTML below to explore this rule: Border-box sizing includes padding and border in the declared width. It helps a full-width card fit its container without arithmetic adjustments. Write your own CSS before opening the solution. Then replace the heading with a longer one and verify that the content is still readable.

.card { box-sizing: border-box; width: 100%; padding: 32px; }

A solution to compare

The HTML supplies the content; the CSS below styles it. Open both together in the playground, then change the lesson rules at the end of the stylesheet.

<article class="card"><span class="badge">This Saturday</span><h2>Neighbourhood repair club</h2><p>Bring a small project. Share a useful skill.</p><a href="#booking">View the workshop</a></article>

body { margin: 0; padding: 24px; font-family: system-ui, sans-serif; color: #25332d; background: #f4f7f2; }
.card { padding: 20px; background: white; border: 1px solid #d4dfd6; }
h2 { margin-top: 0; }
p { line-height: 1.6; }
a { color: #17634c; }
.badge { display: inline-block; margin-bottom: 12px; font-size: .8rem; }
.layout { display: grid; gap: 16px; }
.photo { width: 100%; height: 160px; background: linear-gradient(135deg, #e4af6b, #668cba); }
button, input, select { font: inherit; padding: 8px; }
label { display: block; margin-block: 12px 4px; }

/* This lesson */
.card { box-sizing: border-box; width: 100%; padding: 32px; }

Border-box sizing includes padding and border in the declared width. It helps a full-width card fit its container without arithmetic adjustments.