:root { --max: 920px; }
* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif; line-height: 1.6; }
header, main, aside, footer { width: 100%; max-width: var(--max); margin: 0 auto; padding: 12px 16px; }
nav a { margin-right: 12px; text-decoration: none; }
section, article { border: 1px dashed #bbb; margin: 10px 0; padding: 10px; }
small.muted { color: #666; }