:root { --pad: 24px; }
* { box-sizing: border-box; }
body { font-family: system-ui, sans-serif; margin: 0; padding: var(--pad); background:#f7f7f7; }
main { background:#fff; padding: var(--pad); border-radius: 12px; max-width: 720px; margin: 40px auto; box-shadow: 0 8px 24px rgba(0,0,0,.08); }
h1 { margin-top: 0; }
img { display:block; margin-top: 12px; border-radius: 12px; }