test code block element 2026 a

* { box-sizing: border-box; } iframe { display: block; width: 100%; max-width: 60rem; height: 30em; margin: 1rem auto; } { text-align: center; width: 90%; max-width: 60rem; margin: 0 auto; background: #eee; padding: 2rem; border: 1px solid #000; }