/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #f59e0b;
    --background: #ffffff;
    --background-alt: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-base: 16px;
    --line-height: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;
    
    /* Border radius */
    --border-radius: 8px;
    --border-radius-lg: 16px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

html {
    scroll-behavior: smooth;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.5rem; }

.text-gradient {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-md);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-menu {
    display: flex;
    gap: var(--spacing-lg);
}

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

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: var(--spacing-xl) var(--spacing-md);
    background: linear-gradient(135deg, var(--background) 0%, var(--background-alt) 100%);
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-lg);
}

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

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-visual img {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    border: 2px solid transparent;
    cursor: pointer;
}

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

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

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

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

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

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Sections common */
section {
    padding: var(--spacing-xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

/* Features */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.feature-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

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

/* Demo Section */
.demo-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
    align-items: start;
}

.demo-player {
    position: relative;
}

.demo-player video {
    width: 100%;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.demo-player video.loaded {
    opacity: 1;
}

/* 视频加载动画 */
.video-loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 10;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-md);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.video-loading p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.demo-features ul {
    list-style: none;
}

.demo-features li {
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: var(--spacing-lg);
}

.demo-features li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Pricing */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.pricing-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    position: relative;
    border: 2px solid var(--border-color);
}

.pricing-card.featured {
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.popular-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.promo-badge {
    position: absolute;
    top: -12px;
    right: var(--spacing-md);
    background: linear-gradient(135deg, #ff6b6b, #ee5a6f);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(255, 107, 107, 0.3);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 2px 8px rgba(255, 107, 107, 0.3);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 4px 12px rgba(255, 107, 107, 0.5);
    }
}

.price {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: var(--spacing-md) 0;
}

.price span {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

.pricing-card ul {
    list-style: none;
    margin: var(--spacing-lg) 0;
    text-align: left;
}

.pricing-card li {
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: var(--spacing-lg);
}

.pricing-card li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Download */
.download-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.download-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
}

.os-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.download-card h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.download-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.download-card small {
    color: var(--text-secondary);
    display: block;
    margin-top: var(--spacing-md);
}

/* Footer */
.footer {
    background: var(--background-alt);
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.footer-section h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.footer-section a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    margin-bottom: var(--spacing-sm);
    transition: color 0.2s ease;
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
}
.footer-bottom a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-bottom a:hover {
    color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    :root {
        --font-size-base: 14px;
    }
    
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.25rem; }
    
    .hero {
        flex-direction: column;
        text-align: center;
        padding: calc(var(--spacing-xl) * 2) var(--spacing-md) var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-visual {
        margin-top: var(--spacing-xl);
    }
    
    .demo-content {
        grid-template-columns: 1fr;
    }
    
    .pricing-card.featured {
        transform: none;
    }
    
    .nav-menu {
        display: none;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .features-grid,
    .pricing-grid,
    .download-options {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles */
button:focus-visible,
a:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #0000ff;
        --text-primary: #000000;
        --border-color: #000000;
    }
}

/* Print styles */
@media print {
    .header,
    .hero-actions,
    .footer {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.5;
    }
    
    .hero {
        min-height: auto;
        padding: 1cm 0;
    }
}