* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Arial', sans-serif;
        }

        body {
            padding: 40px 20px;
            background-color: #f5f7fa;
        }

        .page-title {
            text-align: center;
            font-size: 24px;
            font-weight: 700;
            color: #2c3e50;
            margin-bottom: 30px;
        }

        .pcb-container {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 20px;
            max-width: 1400px;
            margin: 0 auto;
        }

        .pcb-card {
            background: #ffffff;
            border-radius: 10px;
            padding: 25px 20px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.08);
            transition: transform 0.3s ease;
        }

        .pcb-card:hover {
            transform: translateY(-5px);
        }

        .card-icon {
            font-size: 32px;
            color: #3498db;
            margin-bottom: 15px;
        }

        .card-title {
            font-size: 18px;
            font-weight: 600;
            color: #2c3e50;
            margin-bottom: 15px;
            padding-bottom: 10px;
            border-bottom: 1px solid #eee;
        }

        .card-content {
            font-size: 14px;
            color: #586675;
            line-height: 1.6;
        }

        .card-content p {
            margin-bottom: 8px;
        }

        /* 响应式适配：小屏幕自动调整列数 */
        @media (max-width: 1200px) {
            .pcb-container {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 768px) {
            .pcb-container {
                grid-template-columns: 1fr;
            }
        }