/* 重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 颜色系统 */
    --primary-color: #007AFF;
    --primary-hover: #0056CC;
    --secondary-color: #5856D6;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --error-color: #FF3B30;
    
    /* 中性色 */
    --white: #FFFFFF;
    --gray-50: #F9FAFB;
    --gray-100: #F3F4F6;
    --gray-200: #E5E7EB;
    --gray-300: #D1D5DB;
    --gray-400: #9CA3AF;
    --gray-500: #6B7280;
    --gray-600: #4B5563;
    --gray-700: #374151;
    --gray-800: #1F2937;
    --gray-900: #111827;
    
    /* 文字颜色 */
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --text-tertiary: #9CA3AF;
    
    /* 背景颜色 */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F9FAFB;
    --bg-tertiary: #F3F4F6;
    
    /* 间距 */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;
    
    /* 圆角 */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px 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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* 过渡 */
    --transition-fast: 0.15s ease-out;
    --transition-normal: 0.25s ease-out;
    --transition-slow: 0.35s ease-out;
}

/* 基础样式 */
html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

@media (max-width: 768px) {
    .container {
        padding: 0 var(--spacing-md);
    }
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--gray-200);
    z-index: 1000;
    transition: all var(--transition-normal);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-md);
}

.brand-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width var(--transition-normal);
}

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

@media (max-width: 768px) {
    .nav-menu {
        gap: var(--spacing-lg);
    }
    
    .brand-name {
        font-size: 1.125rem;
    }
}

/* Hero 区域 */
.hero {
    padding: calc(72px + var(--spacing-4xl)) 0 var(--spacing-4xl);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    overflow: hidden;
    position: relative;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-4xl);
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-lg);
    letter-spacing: -0.02em;
}

.highlight {
    background: linear-gradient(135deg, #FFD700, #FFA500);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-2xl);
    color: rgba(255, 255, 255, 0.9);
}

.hero-actions {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all var(--transition-normal);
    border: none;
    cursor: pointer;
}

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

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

.btn-secondary {
    background-color: transparent;
    color: var(--white);
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
}

.btn-icon {
    width: 20px;
    height: 20px;
    stroke-width: 2;
}

/* 浏览器模拟 */
.browser-mockup {
    background: var(--white);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    transform: perspective(1000px) rotateY(-15deg) rotateX(5deg);
    transition: transform var(--transition-slow);
}

.browser-mockup:hover {
    transform: perspective(1000px) rotateY(-10deg) rotateX(2deg);
}

.browser-header {
    display: flex;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--gray-100);
    border-bottom: 1px solid var(--gray-200);
}

.browser-controls {
    display: flex;
    gap: var(--spacing-sm);
    margin-right: var(--spacing-lg);
}

.control {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.control.close {
    background-color: #FF5F57;
}

.control.minimize {
    background-color: #FFBD2E;
}

.control.maximize {
    background-color: #28CA42;
}

.address-bar {
    flex: 1;
    background: var(--white);
    border-radius: var(--radius-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--gray-300);
}

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

.browser-content {
    height: 300px;
    background: var(--white);
    padding: var(--spacing-lg);
}

.content-placeholder {
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, #f0f0f0 25%, transparent 25%), 
                linear-gradient(-45deg, #f0f0f0 25%, transparent 25%), 
                linear-gradient(45deg, transparent 75%, #f0f0f0 75%), 
                linear-gradient(-45deg, transparent 75%, #f0f0f0 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    border-radius: var(--radius-md);
    opacity: 0.5;
}

@media (max-width: 768px) {
    .hero .container {
        grid-template-columns: 1fr;
        gap: var(--spacing-2xl);
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .hero-actions {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .browser-mockup {
        transform: none;
        max-width: 400px;
        margin: 0 auto;
    }
}

/* 特性区域 */
.features {
    padding: var(--spacing-4xl) 0;
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-4xl);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-2xl);
}

.feature-card {
    background: var(--white);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    border: 1px solid transparent;
}

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

.feature-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.feature-icon svg {
    width: 24px;
    height: 24px;
    stroke: white;
    stroke-width: 2;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

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

@media (max-width: 768px) {
    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .section-title {
        font-size: 2rem;
    }
}

/* 下载区域 */
.download {
    padding: var(--spacing-4xl) 0;
    background: var(--white);
}

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

.download-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.download-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-2xl);
}

.download-options {
    margin-bottom: var(--spacing-2xl);
}

.download-btn {
    display: inline-flex;
    align-items: center;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: var(--spacing-lg) var(--spacing-2xl);
    border-radius: var(--radius-xl);
    text-decoration: none;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-lg);
}

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

.btn-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.btn-icon {
    width: 24px;
    height: 24px;
    stroke-width: 2;
}

.btn-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.btn-label {
    font-size: 1.125rem;
    font-weight: 600;
}

.btn-sublabel {
    font-size: 0.875rem;
    opacity: 0.8;
}

.download-alternatives {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.alt-download {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.alt-download:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.download-info {
    display: flex;
    justify-content: center;
    gap: var(--spacing-2xl);
    flex-wrap: wrap;
}

.info-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.info-item svg {
    width: 16px;
    height: 16px;
    stroke-width: 2;
}

@media (max-width: 768px) {
    .download-title {
        font-size: 2rem;
    }
    
    .download-alternatives {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .download-info {
        gap: var(--spacing-lg);
    }
}

/* 关于区域 */
.about {
    padding: var(--spacing-4xl) 0;
    background: var(--bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-4xl);
    align-items: center;
}

.about-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.about-description {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.stat {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.about-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.image-placeholder {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, var(--gray-100), var(--gray-200));
    border-radius: var(--radius-2xl);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
}

.image-placeholder svg {
    width: 120px;
    height: 120px;
    stroke: var(--gray-400);
    stroke-width: 1.5;
}

@media (max-width: 768px) {
    .about-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-2xl);
        text-align: center;
    }
    
    .about-title {
        font-size: 2rem;
    }
    
    .about-stats {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .image-placeholder {
        width: 250px;
        height: 250px;
    }
}

/* 页脚 */
.footer {
    background: var(--gray-900);
    color: var(--white);
    padding: var(--spacing-4xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-4xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.footer-logo {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-md);
}

.footer-brand-name {
    font-size: 1.25rem;
    font-weight: 600;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-2xl);
}

.link-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--white);
}

.footer-link {
    display: block;
    color: var(--gray-300);
    text-decoration: none;
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: var(--white);
}

.footer-bottom {
    border-top: 1px solid var(--gray-700);
    padding-top: var(--spacing-lg);
    text-align: center;
}

.copyright {
    color: var(--gray-400);
    font-size: 0.875rem;
}

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-2xl);
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
}

/* 滚动效果 */
@media (prefers-reduced-motion: no-preference) {
    .feature-card,
    .stat,
    .download-btn {
        opacity: 0;
        transform: translateY(20px);
        animation: fadeInUp 0.6s ease-out forwards;
    }
    
    .feature-card:nth-child(1) { animation-delay: 0.1s; }
    .feature-card:nth-child(2) { animation-delay: 0.2s; }
    .feature-card:nth-child(3) { animation-delay: 0.3s; }
    .feature-card:nth-child(4) { animation-delay: 0.4s; }
    .feature-card:nth-child(5) { animation-delay: 0.5s; }
    .feature-card:nth-child(6) { animation-delay: 0.6s; }
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 深色模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1F2937;
        --bg-secondary: #111827;
        --bg-tertiary: #374151;
        --text-primary: #F9FAFB;
        --text-secondary: #D1D5DB;
        --text-tertiary: #9CA3AF;
    }
    
    .navbar {
        background: rgba(31, 41, 55, 0.95);
        border-bottom-color: var(--gray-700);
    }
    
    .feature-card,
    .stat {
        background: var(--gray-800);
        border-color: var(--gray-700);
    }
    
    .browser-header {
        background: var(--gray-800);
        border-bottom-color: var(--gray-700);
    }
    
    .address-bar {
        background: var(--gray-700);
        border-color: var(--gray-600);
    }
}