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

        body {
            font-family: 'Microsoft YaHei', Arial, sans-serif;
            line-height: 1.6;
            color: #333;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        }

        .hed19-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        .hed19-header {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        .hed19-nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
        }

        .hed19-logo {
            height: 40px;
        }

        .hed19-nav-menu {
            display: flex;
            gap: 30px;
        }

        .hed19-nav-link {
            text-decoration: none;
            color: #333;
            font-weight: 500;
            transition: all 0.3s ease;
            position: relative;
        }

        .hed19-nav-link:hover {
            color: #667eea;
        }

        .hed19-nav-link::after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            bottom: -5px;
            left: 0;
            background: #667eea;
            transition: width 0.3s ease;
        }

        .hed19-nav-link:hover::after {
            width: 100%;
        }

        .hed19-hero {
            background: linear-gradient(135deg, rgba(102, 126, 234, 0.9), rgba(118, 75, 162, 0.9));
            color: white;
            padding: 80px 0;
            text-align: center;
        }

        .hed19-hero-title {
            font-size: 3.5rem;
            font-weight: 700;
            margin-bottom: 20px;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
        }

        .hed19-hero-subtitle {
            font-size: 1.3rem;
            margin-bottom: 40px;
            opacity: 0.9;
        }

        .hed19-download-section {
            background: white;
            padding: 60px 0;
            margin: -30px 0 0 0;
            border-radius: 30px 30px 0 0;
        }

        .hed19-download-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
            margin-top: 40px;
        }

        .hed19-download-card {
            background: #f8f9ff;
            border-radius: 15px;
            padding: 30px;
            text-align: center;
            border: 2px solid transparent;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }

        .hed19-download-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(102, 126, 234, 0.1), transparent);
            transition: left 0.5s ease;
        }

        .hed19-download-card:hover::before {
            left: 100%;
        }

        .hed19-download-card:hover {
            border-color: #667eea;
            transform: translateY(-5px);
            box-shadow: 0 10px 30px rgba(102, 126, 234, 0.2);
        }

        .hed19-platform-icon {
            font-size: 3rem;
            margin-bottom: 20px;
            color: #667eea;
        }

        .hed19-platform-name {
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 15px;
            color: #333;
        }

        .hed19-version-info {
            color: #666;
            margin-bottom: 20px;
            line-height: 1.8;
        }

        .hed19-download-btn {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            border: none;
            padding: 15px 30px;
            border-radius: 50px;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
            position: relative;
            overflow: hidden;
        }

        .hed19-download-btn::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
            transition: left 0.5s ease;
        }

        .hed19-download-btn:hover::before {
            left: 100%;
        }

        .hed19-download-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
        }

        .hed19-features {
            background: #f8f9ff;
            padding: 80px 0;
        }

        .hed19-section-title {
            text-align: center;
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 50px;
            color: #333;
        }

        .hed19-features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 30px;
        }

        .hed19-feature-card {
            background: white;
            padding: 30px;
            border-radius: 15px;
            text-align: center;
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
            transition: all 0.3s ease;
        }

        .hed19-feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
        }

        .hed19-feature-icon {
            font-size: 2.5rem;
            color: #667eea;
            margin-bottom: 20px;
        }

        .hed19-feature-title {
            font-size: 1.3rem;
            font-weight: 600;
            margin-bottom: 15px;
            color: #333;
        }

        .hed19-feature-desc {
            color: #666;
            line-height: 1.6;
        }

        .hed19-cta-section {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            padding: 80px 0;
            text-align: center;
        }

        .hed19-cta-title {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 20px;
        }

        .hed19-cta-desc {
            font-size: 1.2rem;
            margin-bottom: 40px;
            opacity: 0.9;
        }

        .hed19-cta-btn {
            background: white;
            color: #667eea;
            border: none;
            padding: 20px 40px;
            border-radius: 50px;
            font-size: 1.2rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
        }

        .hed19-cta-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 10px 30px rgba(255, 255, 255, 0.3);
        }

        .hed19-footer {
            background: #2c3e50;
            color: white;
            padding: 50px 0 30px;
        }

        .hed19-footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 30px;
        }

        .hed19-footer-section h3 {
            font-size: 1.3rem;
            margin-bottom: 20px;
            color: #ecf0f1;
        }

        .hed19-footer-section p,
        .hed19-footer-section a {
            color: #bdc3c7;
            text-decoration: none;
            line-height: 1.8;
        }

        .hed19-footer-section a:hover {
            color: #667eea;
        }

        .hed19-footer-bottom {
            border-top: 1px solid #34495e;
            padding-top: 20px;
            text-align: center;
            color: #95a5a6;
        }

        @media (max-width: 768px) {
            .hed19-nav-menu {
                display: none;
            }

            .hed19-hero-title {
                font-size: 2.5rem;
            }

            .hed19-download-grid {
                grid-template-columns: 1fr;
            }

            .hed19-section-title {
                font-size: 2rem;
            }

            .hed19-cta-title {
                font-size: 2rem;
            }
        }

        .hed19-system-requirements {
            background: white;
            padding: 60px 0;
        }

        .hed19-requirements-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
            margin-top: 40px;
        }

        .hed19-requirement-card {
            background: #f8f9ff;
            padding: 25px;
            border-radius: 10px;
            border-left: 4px solid #667eea;
        }

        .hed19-requirement-title {
            font-weight: 600;
            color: #333;
            margin-bottom: 10px;
        }

        .hed19-requirement-list {
            list-style: none;
            color: #666;
        }

        .hed19-requirement-list li {
            padding: 5px 0;
            position: relative;
            padding-left: 20px;
        }

        .hed19-requirement-list li::before {
            content: '✓';
            position: absolute;
            left: 0;
            color: #667eea;
            font-weight: bold;
        }