:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #10b981;
    --background: #ffffff;
    --surface: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --border-radius: 8px;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

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

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
}

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

/* Header */
.header {
    background: var(--background);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--text-primary);
    text-decoration: none;
    transition: opacity 0.2s;
}

.logo:hover {
    opacity: 0.8;
}

.logo-icon {
    width: 32px;
    height: 32px;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    padding: 80px 0 120px;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 24px;
}

.highlight {
    color: var(--primary-color);
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s;
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border-color: var(--border);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-1px);
}

.btn-icon {
    width: 20px;
    height: 20px;
}

.app-screenshot {
    width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    background: var(--surface);
    padding: 20px;
    border: 1px solid var(--border);
}

/* Sections */
.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 60px;
    color: var(--text-primary);
}

/* Features */
.features {
    padding: 100px 0;
    background: var(--background);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 32px;
    background: var(--surface);
    border-radius: var(--border-radius);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.feature-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.feature-card a:hover {
    text-decoration: underline;
}

/* Technology Section */
.technology {
    padding: 100px 0;
    background: var(--surface);
}

.tech-intro {
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 48px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-bottom: 48px;
}

.tech-card {
    padding: 32px;
    background: var(--background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border);
    transition: all 0.2s;
    text-align: center;
}

.tech-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.tech-icon {
    font-size: 3rem;
    margin-bottom: 16px;
    color: var(--primary-color);
    display: flex;
    justify-content: center;
}

.tech-icon svg {
    color: var(--primary-color);
}

.tech-card h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.tech-card h3 a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.2s;
}

.tech-card h3 a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

.tech-card p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

.tech-benefits {
    background: var(--background);
    padding: 32px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border);
}

.tech-benefits h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
    text-align: center;
}

.tech-benefits ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 16px;
}

.tech-benefits li {
    padding: 12px 0;
    color: var(--text-secondary);
    line-height: 1.6;
}

.tech-benefits strong {
    color: var(--primary-color);
    font-weight: 600;
}

/* Use Cases */
.use-cases {
    padding: 100px 0;
    background: var(--surface);
}

.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.use-case {
    padding: 24px;
    background: var(--background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.use-case:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.use-case h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.use-case p {
    color: var(--text-secondary);
}

/* Download */
.download {
    padding: 100px 0;
    background: var(--background);
}

.download-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.download-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
    margin-bottom: 60px;
}

.step {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.step-number {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.5rem;
    margin-bottom: 16px;
}

.step-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.step-content p {
    color: var(--text-secondary);
}

.download-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px;
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--border-radius);
    text-decoration: none;
    transition: all 0.2s;
}

.download-btn:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.download-icon {
    font-size: 2rem;
}

.download-info {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.download-platform {
    font-weight: 600;
    color: var(--text-primary);
}

.download-format {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.version-info {
    color: var(--text-secondary);
    margin-top: 24px;
}

.version-info a {
    color: var(--primary-color);
    text-decoration: none;
}

.version-info a:hover {
    text-decoration: underline;
}

/* Documentation */
.documentation {
    padding: 100px 0;
    background: var(--surface);
}

.docs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.doc-card {
    padding: 32px;
    background: var(--background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.doc-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.doc-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.doc-card p {
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.6;
}

.doc-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s;
}

.doc-link:hover {
    color: var(--primary-dark);
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 1.25rem;
    margin-bottom: 16px;
}

.footer-logo-icon {
    width: 24px;
    height: 24px;
}

.footer-info p {
    color: #94a3b8;
    line-height: 1.6;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-section h4 {
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 8px;
}

.footer-section a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 20px;
    text-align: center;
    color: #94a3b8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .tech-grid {
        grid-template-columns: 1fr;
    }
    
    .tech-benefits ul {
        grid-template-columns: 1fr;
    }
    
    .nav-links {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block !important;
        background: none;
        border: none;
        font-size: 1.5rem;
        cursor: pointer;
        color: var(--text-primary);
        padding: 8px;
        transition: color 0.2s;
    }
    
    .mobile-menu-btn:hover {
        color: var(--primary-color);
    }
    
    .nav {
        position: relative;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
    
    .hero {
        padding: 40px 0 60px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-description {
        font-size: 1.125rem;
    }
    
    .btn {
        padding: 10px 20px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features,
    .use-cases,
    .download,
    .documentation {
        padding: 60px 0;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus styles for accessibility */
.btn:focus,
.nav-links a:focus,
.doc-link:focus,
.download-btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Loading animation for screenshot placeholder */
.app-screenshot[src="screenshot.png"] {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}