body{margin:0;font-family:Segoe UI;background:#111;color:#fff;}
.layout{display:grid;grid-template-columns:250px 1fr 250px;gap:20px;padding:20px;}
.card{background:#1e1e1e;padding:15px;margin-bottom:15px;border-radius:8px;}
@media(max-width:900px){.layout{grid-template-columns:1fr;}}