body { font-family: sans-serif; background-color: #f9f9f9; }
        .detail-box {
            background: white;
            width: 80%;
            margin: 50px auto;
            padding: 20px;
            display: flex; 
            gap: 30px;
            box-shadow: 0 0 10px rgba(0,0,0,0.1);
        }

        .left-col img {
            width: 100%;
            max-width: 400px;
            height: auto;
            border-radius: 5px;
        }

        .right-col {
            flex: 1;
        }

        .price {
            color: red;
            font-size: 24px;
            font-weight: bold;
        }

        .btn-action {
            padding: 10px 20px;
            text-decoration: none;
            color: white;
            border-radius: 4px;
            display: inline-block;
            margin-top: 10px;
        }

        .btn-checkout { background-color: #28a745; }
        .btn-back { background-color: #6c757d; }