body{font-family:Roboto,sans-serif;margin:0;padding:0;background:#f4f4f9;color:#222}header{background:#0077cc;color:#fff;padding:20px;text-align:center}nav ul{list-style:none;padding:0}nav ul li{display:inline-block;margin:0 15px}nav ul li a{text-decoration:none;color:#fff;font-weight:700}button{background:#0077cc;color:#fff;border:none;padding:10px 20px;margin:10px;border-radius:5px;cursor:pointer}button:hover{background:#005fa3}.order-book,.trade-panel{margin:20px;padding:20px;border:1px solid #ccc;background:#fff;border-radius:5px}