body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            line-height: 1.6;
            margin: 0;
            padding: 20px;
            background-color: #f0f2f5;
            color: #333;
        }
        .container {
            max-width: 1400px;
            margin: 0 auto;
            background: #fff;
            padding: 30px;
            border-radius: 12px;
            box-shadow: 0 6px 20px rgba(0,0,0,0.08);
        }
        
        /* 步骤导航 */
        .step-nav {
            display: flex;
            justify-content: center;
            margin-bottom: 40px;
            border-bottom: 2px solid #e8e8e8;
            padding-bottom: 20px;
        }
        .step-item {
            flex: 1;
            text-align: center;
            padding: 15px 10px;
            cursor: pointer;
            border-radius: 8px;
            margin: 0 5px;
            transition: all 0.3s ease;
            position: relative;
        }
        .step-item:not(.active):not(.completed) {
            background: #f8f9fa;
            color: #666;
        }
        .step-item.active {
            background: linear-gradient(135deg, #4285F4, #34A853);
            color: white;
            box-shadow: 0 4px 12px rgba(66, 133, 244, 0.3);
        }
        .step-item.completed {
            background: #e6f4ea;
            color: #1e8e3e;
            border: 2px solid #34A853;
        }
        .step-item.completed::after {
            content: '✓';
            position: absolute;
            top: 5px;
            right: 10px;
            background: #34A853;
            color: white;
            border-radius: 50%;
            width: 20px;
            height: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 12px;
            font-weight: bold;
        }
        .step-number {
            display: block;
            font-size: 24px;
            font-weight: bold;
            margin-bottom: 5px;
        }
        .step-title {
            font-size: 14px;
            font-weight: 600;
        }
        .step-desc {
            font-size: 12px;
            opacity: 0.8;
            margin-top: 2px;
        }
        
        /* 步骤内容 */
        .step-content {
            display: none;
        }
        .step-content.active {
            display: block;
        }
        
        /* 数据传递按钮 */
        .transfer-btn {
            background: linear-gradient(135deg, #FF9500, #FF6B35);
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 8px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            margin: 20px auto;
            display: block;
            transition: all 0.3s ease;
            box-shadow: 0 4px 12px rgba(255, 149, 0, 0.3);
        }
        .transfer-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(255, 149, 0, 0.4);
        }
        .transfer-btn:disabled {
            background: #ccc;
            cursor: not-allowed;
            transform: none;
            box-shadow: none;
        }
        
        /* 成功提示 */
        .transfer-success {
            background: #e6f4ea;
            color: #1e8e3e;
            padding: 15px;
            border-radius: 8px;
            text-align: center;
            margin: 20px 0;
            display: none;
            border-left: 4px solid #34A853;
        }
        
        /* 响应式设计 */
        @media (max-width: 1200px) {
            .step-nav {
                flex-wrap: wrap;
            }
            .step-item {
                flex-basis: calc(50% - 10px);
                margin-bottom: 10px;
            }
        }
        @media (max-width: 600px) {
            .step-item {
                flex-basis: 100%;
            }
        }
        
        /* 动画 */
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
    </style>