:root {
            /* Color System */
            --primary-500: #007AFF;
            --primary-600: #005ECB;
            --bg-page: #F5F5F7;
            --bg-surface: #FFFFFF;
            --text-primary: #1D1D1F;
            --text-secondary: #6E6E73;
            --border-subtle: #D2D2D7;
            --semantic-success: #34C759;
            --semantic-warning: #FF9500;
            
            /* Spacing System (4px grid) */
            --space-xs: 8px;
            --space-sm: 16px;
            --space-md: 24px;
            --space-lg: 32px;
            --space-xl: 48px;
            --space-xxl: 64px;
            --space-xxxl: 96px;
            
            /* Border Radius */
            --radius-sm: 8px;
            --radius-md: 16px;
            --radius-lg: 24px;
            
            /* Shadows */
            --shadow-md: 0 8px 16px rgba(0, 122, 255, 0.08);
            --shadow-lg: 0 16px 32px rgba(0, 122, 255, 0.12);
            
            /* Typography */
            --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        html {
            scroll-behavior: smooth;
            overflow-x: hidden;
        }
        
        body {
            font-family: var(--font-family);
            background-color: var(--bg-page);
            color: var(--text-primary);
            line-height: 1.7;
            overflow-x: hidden;
        }
        
        /* Typography Scale */
        .display {
            font-size: 64px;
            font-weight: 700;
            line-height: 1.2;
            letter-spacing: -0.02em;
        }
        
        .heading-xl {
            font-size: 40px;
            font-weight: 700;
            line-height: 1.3;
            letter-spacing: -0.02em;
        }
        
        .heading-lg {
            font-size: 24px;
            font-weight: 600;
            line-height: 1.4;
            letter-spacing: -0.01em;
        }
        
        .body-large {
            font-size: 18px;
            line-height: 1.6;
        }
        
        .body {
            font-size: 16px;
            line-height: 1.7;
        }
        
        .text-small {
            font-size: 14px;
            font-weight: 500;
            line-height: 1.5;
        }
        
        /* Layout Components */
        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 var(--space-xl);
        }
        
        .section {
            padding: var(--space-xxxl) 0;
        }
        
        .grid {
            display: grid;
            gap: var(--space-md);
        }
        
        .grid-3 {
            grid-template-columns: repeat(3, 1fr);
        }
        
        .grid-2 {
            grid-template-columns: repeat(2, 1fr);
        }
        
        /* Navigation */
        .nav {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            background: rgba(245, 245, 247, 0.8);
            backdrop-filter: blur(20px);
            border-bottom: 1px solid var(--border-subtle);
            z-index: 1000;
            transition: all 0.3s ease;
        }
        
        .nav.scrolled {
            background: rgba(255, 255, 255, 0.9);
            box-shadow: var(--shadow-md);
        }
        
        .nav-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: var(--space-sm) var(--space-xl);
            max-width: 1280px;
            margin: 0 auto;
        }
        
        .nav-logo {
            font-size: 24px;
            font-weight: 700;
            color: var(--text-primary);
            text-decoration: none;
        }
        
        .nav-links {
            display: flex;
            list-style: none;
            gap: var(--space-lg);
        }
        
        .nav-link {
            color: var(--text-secondary);
            text-decoration: none;
            font-weight: 500;
            transition: color 0.2s ease;
            padding: var(--space-xs) var(--space-sm);
            border-radius: var(--radius-sm);
        }
        
        .nav-link:hover {
            color: var(--primary-500);
            background: rgba(0, 122, 255, 0.1);
        }
        
        .nav-toggle {
            display: none;
            background: none;
            border: none;
            font-size: 24px;
            color: var(--text-primary);
            cursor: pointer;
        }
        
        /* Hero Section */
        .hero {
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            position: relative;
            background: linear-gradient(135deg, var(--bg-page) 0%, rgba(0, 122, 255, 0.03) 50%, rgba(255, 255, 255, 0.8) 100%);
            overflow: hidden;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: 
                radial-gradient(circle at 20% 80%, rgba(0, 122, 255, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 20%, rgba(255, 149, 0, 0.05) 0%, transparent 50%),
                radial-gradient(circle at 40% 40%, rgba(52, 199, 89, 0.05) 0%, transparent 50%);
            animation: float 20s ease-in-out infinite;
        }
        
        @keyframes float {
            0%, 100% { transform: translateY(0px) rotate(0deg); }
            33% { transform: translateY(-10px) rotate(1deg); }
            66% { transform: translateY(-5px) rotate(-1deg); }
        }
        
        .hero-content {
            position: relative;
            z-index: 2;
            max-width: 800px;
            padding: var(--space-xxxl) var(--space-xl);
            animation: heroFadeIn 1s ease-out 0.3s both;
        }
        
        @keyframes heroFadeIn {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        
        .hero-title {
            margin-bottom: var(--space-lg);
            background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary-500) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        
        .hero-subtitle {
            color: var(--text-secondary);
            margin-bottom: var(--space-xl);
            max-width: 650px;
            margin-left: auto;
            margin-right: auto;
        }
        
        .hero-cta {
            display: inline-flex;
            align-items: center;
            gap: var(--space-xs);
            background: var(--primary-500);
            color: white;
            padding: var(--space-sm) var(--space-lg);
            border-radius: var(--radius-sm);
            text-decoration: none;
            font-weight: 600;
            transition: all 0.2s ease;
            box-shadow: var(--shadow-md);
        }
        
        .hero-cta:hover {
            background: var(--primary-600);
            transform: scale(1.03);
            box-shadow: var(--shadow-lg);
        }
        
        /* Cards */
        .card {
            background: var(--bg-surface);
            padding: var(--space-lg);
            border-radius: var(--radius-md);
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
            transition: all 0.25s ease;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }
        
        .card:hover {
            transform: translateY(-8px);
            box-shadow: var(--shadow-md);
        }
        
        .card-icon {
            width: 48px;
            height: 48px;
            background: var(--primary-500);
            border-radius: var(--radius-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: var(--space-sm);
            color: white;
        }
        
        .card-title {
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }
        
        .card-description {
            color: var(--text-secondary);
        }
        
        /* Demo Section */
        .demo-section {
            background: rgba(255, 255, 255, 0.6);
            backdrop-filter: blur(20px);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: var(--radius-lg);
            margin: var(--space-xl) 0;
            padding: var(--space-xl);
            position: relative;
            overflow: hidden;
        }
        
        .demo-section::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: linear-gradient(45deg, rgba(0, 122, 255, 0.05) 0%, transparent 50%);
            pointer-events: none;
        }
        
        .demo-container {
            position: relative;
            z-index: 2;
        }
        
        .demo-input {
            width: 100%;
            height: 56px;
            background: var(--bg-surface);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-sm);
            padding: 0 var(--space-sm);
            font-size: 16px;
            transition: all 0.2s ease;
            margin-bottom: var(--space-sm);
        }
        
        .demo-input:focus {
            outline: none;
            border-color: var(--primary-500);
            box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
        }
        
        .demo-output {
            background: var(--bg-page);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-sm);
            padding: var(--space-sm);
            min-height: 120px;
            margin-top: var(--space-sm);
            font-family: 'Courier New', monospace;
            font-size: 14px;
            line-height: 1.5;
            white-space: pre-wrap;
        }
        
        /* Buttons */
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: var(--space-xs);
            padding: 12px 24px;
            border: none;
            border-radius: var(--radius-sm);
            font-size: 14px;
            font-weight: 500;
            text-decoration: none;
            cursor: pointer;
            transition: all 0.2s ease;
            height: 48px;
        }
        
        .btn-primary {
            background: var(--primary-500);
            color: white;
        }
        
        .btn-primary:hover {
            background: var(--primary-600);
            transform: scale(1.03);
        }
        
        .btn-secondary {
            background: transparent;
            color: var(--primary-500);
            border: 1px solid var(--primary-500);
        }
        
        .btn-secondary:hover {
            background: var(--primary-500);
            color: white;
        }
        
        /* Forms */
        .form-group {
            margin-bottom: var(--space-sm);
        }
        
        .form-label {
            display: block;
            margin-bottom: var(--space-xs);
            font-weight: 500;
            color: var(--text-primary);
        }
        
        .form-input {
            width: 100%;
            height: 48px;
            background: var(--bg-surface);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-sm);
            padding: 0 var(--space-sm);
            font-size: 16px;
            transition: all 0.2s ease;
        }
        
        .form-input:focus {
            outline: none;
            border-color: var(--primary-500);
            box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
        }
        
        .form-textarea {
            width: 100%;
            background: var(--bg-surface);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-sm);
            padding: var(--space-sm);
            font-size: 16px;
            font-family: var(--font-family);
            resize: vertical;
            min-height: 120px;
            transition: all 0.2s ease;
        }
        
        .form-textarea:focus {
            outline: none;
            border-color: var(--primary-500);
            box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
        }
        
        /* Newsletter */
        .newsletter {
            background: linear-gradient(135deg, var(--primary-500) 0%, var(--primary-600) 100%);
            color: white;
            text-align: center;
            border-radius: var(--radius-lg);
            padding: var(--space-xl);
            margin: var(--space-xl) 0;
        }
        
        .newsletter-form {
            display: flex;
            gap: var(--space-sm);
            max-width: 400px;
            margin: 0 auto;
        }
        
        .newsletter-input {
            flex: 1;
            height: 48px;
            background: rgba(255, 255, 255, 0.9);
            border: 1px solid rgba(255, 255, 255, 0.3);
            border-radius: var(--radius-sm);
            padding: 0 var(--space-sm);
            color: var(--text-primary);
        }
        
        .newsletter-input::placeholder {
            color: var(--text-secondary);
        }
        
        /* Stats */
        .stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: var(--space-lg);
            margin: var(--space-xl) 0;
        }
        
        .stat-item {
            text-align: center;
            padding: var(--space-lg);
            background: var(--bg-surface);
            border-radius: var(--radius-md);
        }
        
        .stat-number {
            font-size: 32px;
            font-weight: 700;
            color: var(--primary-500);
            display: block;
        }
        
        .stat-label {
            color: var(--text-secondary);
            margin-top: var(--space-xs);
        }
        
        /* Animations */
        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: all 0.6s ease;
        }
        
        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }
        
        .slide-up {
            opacity: 0;
            transform: translateY(50px);
            transition: all 0.8s ease;
        }
        
        .slide-up.visible {
            opacity: 1;
            transform: translateY(0);
        }
        
        /* Mobile Menu */
        .nav-mobile {
            position: fixed;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100vh;
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(20px);
            z-index: 999;
            transition: left 0.3s ease;
            padding: var(--space-xxxl) var(--space-xl);
        }
        
        .nav-mobile.open {
            left: 0;
        }
        
        .nav-mobile-list {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: var(--space-lg);
        }
        
        .nav-mobile-link {
            color: var(--text-primary);
            text-decoration: none;
            font-size: 24px;
            font-weight: 600;
            padding: var(--space-sm);
            border-radius: var(--radius-sm);
            transition: all 0.2s ease;
        }
        
        .nav-mobile-link:hover {
            background: rgba(0, 122, 255, 0.1);
            color: var(--primary-500);
        }
        
        /* Responsive Design */
        @media (max-width: 768px) {
            .display {
                font-size: 40px;
            }
            
            .heading-xl {
                font-size: 28px;
            }
            
            .container {
                padding: 0 var(--space-sm);
            }
            
            .nav-links {
                display: none;
            }
            
            .nav-toggle {
                display: block;
            }
            
            .grid-3 {
                grid-template-columns: 1fr;
            }
            
            .grid-2 {
                grid-template-columns: 1fr;
            }
            
            .hero {
                min-height: 80vh;
            }
            
            .hero-content {
                padding: var(--space-xl) var(--space-sm);
            }
            
            .section {
                padding: var(--space-xl) 0;
            }
            
            .newsletter-form {
                flex-direction: column;
            }
            
            .stats {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .demo-section {
                margin: var(--space-sm) 0;
                padding: var(--space-lg);
            }
        }
        
        @media (max-width: 480px) {
            .stats {
                grid-template-columns: 1fr;
            }
        }
        
        /* Accessibility */
        @media (prefers-reduced-motion: reduce) {
            *,
            *::before,
            *::after {
                animation-duration: 0.01ms !important;
                animation-iteration-count: 1 !important;
                transition-duration: 0.01ms !important;
            }
        }
        
        /* Loading Animation */
        .loading {
            display: inline-block;
            width: 20px;
            height: 20px;
            border: 2px solid rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            border-top-color: white;
            animation: spin 1s ease-in-out infinite;
        }
        
        @keyframes spin {
            to { transform: rotate(360deg); }
        }
        
        /* Success Messages */
        .success-message {
            background: var(--semantic-success);
            color: white;
            padding: var(--space-sm);
            border-radius: var(--radius-sm);
            text-align: center;
            margin-top: var(--space-sm);
            opacity: 0;
            transform: translateY(-10px);
            transition: all 0.3s ease;
        }
        
        .success-message.show {
            opacity: 1;
            transform: translateY(0);
        }