body{max-width:800px;margin:2rem auto;font:16px/1.5 system-ui,sans-serif}
nav{margin-bottom:1rem}
.board{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px;margin-top:1rem}
.card{border:1px solid #ddd;border-radius:8px;padding:12px;background:#fff}