/* 基础样式和变量定义 */
:root {
    /* 浅色主题变量 */
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --text-primary: #333333;
    --text-secondary: #666666;
    --accent-primary: #4a6bff;
    --accent-secondary: #6c757d;
    --border-color: #e0e0e0;
    --card-bg: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    
    /* 过渡动画 */
    --transition: all 0.3s ease;
    
    /* 安全颜色 */
    --safe-bg: #f8f9fa;
    --safe-text: #212529;
    --safe-border: #dee2e6;
}

/* 深色主题变量 */
body.dark-theme {
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --accent-primary: #6c8bff;
    --accent-secondary: #adb5bd;
    --border-color: #333333;
    --card-bg: #252525;
    --shadow-color: rgba(0, 0, 0, 0.5);
    
    --safe-bg: #212529;
    --safe-text: #f8f9fa;
    --safe-border: #343a40;
}

/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: var(--transition);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 容器样式 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部样式 */
.header {
    background-color: var(--bg-secondary);
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo img {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    object-fit: cover;
}

.logo h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

/* 主题切换按钮 */
.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: var(--border-color);
}

.theme-toggle:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* 英雄区域样式 */
.hero {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 40px;
}

.app-info h2 {
    font-size: 48px;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.app-info .version {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.app-info .description {
    font-size: 20px;
    color: var(--text-secondary);
    max-width: 800px;
    margin-bottom: 32px;
    line-height: 1.8;
}

.app-icon img {
    width: 180px;
    height: 180px;
    border-radius: 32px;
    object-fit: cover;
    box-shadow: 0 10px 30px var(--shadow-color);
    border: 4px solid var(--card-bg);
}

/* 下载按钮样式 */
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background-color: var(--accent-primary);
    color: white;
    padding: 16px 32px;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    min-width: 180px;
}

.download-btn:hover {
    background-color: #3a56e0;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(74, 107, 255, 0.3);
}

.download-btn:active {
    transform: translateY(0);
}

.download-btn:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

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

.download-btn.primary:hover {
    background-color: #3a56e0;
}

.btn-icon {
    margin-right: 8px;
}

/* 特性区域样式 */
.features {
    padding: 100px 0;
    background-color: var(--bg-primary);
}

.features h3 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 60px;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.feature-card {
    background-color: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 5px 20px var(--shadow-color);
    transition: var(--transition);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--shadow-color);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background-color: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
    color: var(--accent-primary);
}

.feature-card h4 {
    font-size: 24px;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* 下载区域样式 */
.download-section {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.download-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 30px;
    background-color: var(--card-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow-color);
}

.download-icon {
    width: 120px;
    height: 120px;
    border-radius: 24px;
    object-fit: cover;
    border: 3px solid var(--border-color);
}

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

.download-info h3 {
    font-size: 32px;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.download-info p {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

/* 页脚样式 */
.footer {
    background-color: var(--bg-secondary);
    padding: 40px 0;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    margin-bottom: 30px;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 16px;
    transition: var(--transition);
}

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

.footer-info {
    text-align: center;
}

.footer-info p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 8px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero {
        padding: 60px 0;
    }
    
    .app-info h2 {
        font-size: 36px;
    }
    
    .app-info .description {
        font-size: 18px;
    }
    
    .app-icon img {
        width: 150px;
        height: 150px;
    }
    
    .features {
        padding: 80px 0;
    }
    
    .features h3 {
        font-size: 30px;
        margin-bottom: 40px;
    }
    
    .features-grid {
        gap: 30px;
    }
    
    .feature-card {
        padding: 30px;
    }
    
    .download-container {
        flex-direction: column;
        text-align: center;
        padding: 30px;
    }
    
    .download-info {
        align-items: center;
    }
    
    .footer-links {
        flex-direction: column;
        align-items: center;
        gap: 15px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 40px 0;
    }
    
    .app-info h2 {
        font-size: 28px;
    }
    
    .app-info .description {
        font-size: 16px;
    }
    
    .app-icon img {
        width: 120px;
        height: 120px;
    }
    
    .download-btn {
        width: 100%;
        padding: 14px 24px;
        font-size: 16px;
    }
    
    .features {
        padding: 60px 0;
    }
    
    .features h3 {
        font-size: 24px;
    }
    
    .feature-card {
        padding: 20px;
    }
    
    .feature-card h4 {
        font-size: 20px;
    }
}

/* 安全样式 */
.safe-area {
    background-color: var(--safe-bg);
    color: var(--safe-text);
    border: 1px solid var(--safe-border);
}

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

/* 焦点样式增强 */
button:focus-visible,
 a:focus-visible {
    outline: 3px solid var(--accent-primary);
    outline-offset: 2px;
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --shadow-color: rgba(0, 0, 0, 0.3);
    }
    
    body.dark-theme {
        --border-color: #ffffff;
        --shadow-color: rgba(255, 255, 255, 0.1);
    }
}