:root { font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, sans-serif; }
body { margin: 0; line-height: 1.6; }
nav { display: flex; gap: 1rem; padding: 1rem; background: #fafafa; border-bottom: 1px solid #eee; }
main { max-width: 900px; margin: 0 auto; padding: 1.25rem; }
.card { border: 1px solid #ddd; border-radius: 8px; padding: 1rem; margin: 1rem 0; }
footer { max-width: 900px; margin: 0 auto; padding: 1.25rem; color: #666; }