* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Microsoft YaHei', '微软雅黑', Arial, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 40px 20px;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
        }

        .header {
            text-align: center;
            color: white;
            margin-bottom: 50px;
        }

        .header h1 {
            font-size: 3em;
            margin-bottom: 15px;
            text-shadow: 0 4px 10px rgba(0,0,0,0.3);
        }

        .header p {
            font-size: 1.3em;
            opacity: 0.95;
            text-shadow: 0 2px 5px rgba(0,0,0,0.2);
        }

        .intro-card {
            background: white;
            border-radius: 20px;
            padding: 40px;
            margin-bottom: 40px;
            box-shadow: 0 10px 40px rgba(0,0,0,0.2);
        }

        .intro-card h2 {
            color: #667eea;
            font-size: 2em;
            margin-bottom: 20px;
        }

        .intro-card p {
            color: #555;
            line-height: 1.8;
            font-size: 1.1em;
            margin-bottom: 15px;
        }

        .container > .demos-grid {
            display: grid;
            grid-template-columns: repeat(4, minmax(0, 1fr));
            gap: 20px;
            margin-bottom: 40px;
        }

        .demo-card {
            display: flex;
            flex-direction: column;
            background: white;
            border-radius: 20px;
            overflow: hidden;
            box-shadow: 0 10px 40px rgba(0,0,0,0.2);
            transition: all 0.3s;
            cursor: pointer;
        }

        .demo-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 50px rgba(0,0,0,0.3);
        }

        .demo-icon {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            padding: 28px;
            text-align: center;
            font-size: 4em;
        }

        .demo-content {
            display: flex;
            flex-direction: column;
            flex: 1;
            padding: 22px;
        }

        .demo-content h3 {
            color: #333;
            font-size: 1.4em;
            line-height: 1.4;
            margin-bottom: 15px;
        }

        .demo-content p {
            color: #666;
            line-height: 1.6;
            margin-bottom: 20px;
        }

        .demo-features {
            list-style: none;
            margin-bottom: 20px;
        }

        .demo-features li {
            color: #555;
            padding: 8px 0;
            border-bottom: 1px solid #eee;
        }

        .demo-features li:before {
            content: "✓ ";
            color: #667eea;
            font-weight: bold;
            margin-right: 8px;
        }

        .demo-features li:last-child {
            border-bottom: none;
        }

        .demo-button {
            display: block;
            margin-top: auto;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            text-align: center;
            padding: 15px;
            border-radius: 10px;
            text-decoration: none;
            font-weight: bold;
            font-size: 1.1em;
            transition: all 0.3s;
        }

        .demo-button:hover {
            transform: scale(1.05);
            box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
        }

        @media (max-width: 1023px) {
            .container > .demos-grid {
                grid-template-columns: repeat(2, minmax(0, 1fr));
            }
        }

        @media (max-width: 600px) {
            .container > .demos-grid {
                grid-template-columns: minmax(0, 1fr);
            }
        }

        .footer {
            text-align: center;
            color: white;
            margin-top: 50px;
            padding-top: 30px;
            border-top: 2px solid rgba(255,255,255,0.2);
        }

        .footer p {
            margin-bottom: 10px;
            opacity: 0.9;
        }

        .timeline {
            background: white;
            border-radius: 20px;
            padding: 40px;
            margin-bottom: 40px;
            box-shadow: 0 10px 40px rgba(0,0,0,0.2);
        }

        .timeline h2 {
            color: #667eea;
            font-size: 2em;
            margin-bottom: 30px;
            text-align: center;
        }

        .timeline-item {
            display: flex;
            margin-bottom: 30px;
            padding: 20px;
            background: #f8f9fa;
            border-radius: 10px;
            border-left: 5px solid #667eea;
        }

        .timeline-number {
            background: #667eea;
            color: white;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5em;
            font-weight: bold;
            margin-right: 20px;
            flex-shrink: 0;
        }

        .timeline-content h3 {
            color: #333;
            margin-bottom: 10px;
        }

        .timeline-content p {
            color: #666;
            line-height: 1.6;
        }