:root {
    --primary-color: #3B82F6;
    --primary-dark: #1D4ED8;
    --secondary-color: #10B981;
    --accent-color: #F59E0B;
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --text-muted: #9CA3AF;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F9FAFB;
    --bg-card: #FFFFFF;
    --border-color: #E5E7EB;
    --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);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --text-primary: #F9FAFB;
    --text-secondary: #D1D5DB;
    --text-muted: #9CA3AF;
    --bg-primary: #111827;
    --bg-secondary: #1F2937;
    --bg-card: #374151;
    --border-color: #4B5563;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: var(--transition);
}

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

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

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

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: var(--transition);
}

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

/* 主题切换按钮 */
.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50px;
    padding: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    position: relative;
    width: 44px;
    height: 44px;
}

.theme-toggle:hover {
    border-color: var(--primary-color);
    transform: scale(1.1);
}

.sun-icon,
.moon-icon {
    position: absolute;
    transition: var(--transition);
}

.sun-icon {
    opacity: 1;
    transform: rotate(0deg);
}

.moon-icon {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .sun-icon {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .moon-icon {
    opacity: 1;
    transform: rotate(0deg);
}

/* 主要内容 */
main {
    margin-top: 70px;
}

/* 英雄区域 */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 70% 30%, rgba(59, 130, 246, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 16px;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 24px;
    color: var(--text-secondary);
    margin-bottom: 24px;
    font-weight: 600;
}

.hero-description {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.7;
}

.hero-stats {
    display: flex;
    gap: 40px;
    margin-bottom: 40px;
}

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

.stat-number {
    font-size: 32px;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
    font-weight: 500;
}

.hero-actions {
    display: flex;
    gap: 20px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 16px 32px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    position: relative;
    overflow: hidden;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

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

.hero-image img {
    max-width: 100%;
    height: auto;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    object-fit: cover;
}

/* 功能特色 */
.features {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.section-title {
    font-size: 40px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 60px;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.feature-card {
    background-color: var(--bg-card);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.feature-icon {
    margin-bottom: 24px;
    display: flex;
    justify-content: center;
}

.feature-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

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

/* 下载中心 */
.download {
    padding: 80px 0;
    background-color: var(--bg-primary);
}

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

.app-info {
    display: flex;
    align-items: center;
    gap: 30px;
}

.app-details h3 {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.app-version,
.app-size,
.app-requirement {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.download-actions {
    display: flex;
    justify-content: center;
    align-items: center;
}

.btn-download {
    background-color: var(--secondary-color);
    color: white;
    padding: 20px 40px;
    font-size: 18px;
    box-shadow: var(--shadow-md);
}

.btn-download:hover {
    background-color: #059669;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}



.download-notice {
    background-color: var(--bg-secondary);
    padding: 30px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.download-notice h4 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.download-notice ul {
    list-style: none;
    padding: 0;
}

.download-notice li {
    color: var(--text-secondary);
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.download-notice li::before {
    content: '•';
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* 安全与合规 */
.security {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.security-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.security-card {
    background-color: var(--bg-card);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.security-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.security-icon {
    margin-bottom: 24px;
    display: flex;
    justify-content: center;
}

.security-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

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

/* 页脚 */
.footer {
    background-color: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: 60px 0 20px;
}

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

.footer-section h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
}

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

.footer-section li {
    margin-bottom: 12px;
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-section span {
    color: var(--text-secondary);
    font-size: 14px;
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}

.footer-bottom-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-bottom p {
    color: var(--text-muted);
    font-size: 14px;
}

.footer-bottom-links {
    display: flex;
    gap: 20px;
    color: var(--text-muted);
    font-size: 14px;
}

/* 备案链接样式 */
.beian-link {
    color: var(--text-muted);
    text-decoration: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

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

.police-beian img {
    width: 14px;
    height: 14px;
    vertical-align: middle;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .download-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .app-info {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero-title {
        font-size: 40px;
    }
    
    .hero-subtitle {
        font-size: 20px;
    }
    
    .hero-description {
        font-size: 16px;
    }
    
    .hero-stats {
        justify-content: center;
        gap: 20px;
    }
    
    .stat-number {
        font-size: 24px;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .security-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-bottom-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 60px 0;
    }
    
    .features,
    .download,
    .security {
        padding: 60px 0;
    }
    
    .feature-card,
    .security-card {
        padding: 30px 20px;
    }
    
    .app-info {
        flex-direction: column;
        text-align: center;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feature-card,
.security-card {
    animation: fadeInUp 0.6s ease-out;
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* 焦点样式 */
button:focus,
a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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