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

/* 全局变量定义 */
:root {
    /* 颜色 */
    --primary-color: #7289da;
    --primary-dark: #677bc4;
    --secondary-color: #5865f2;
    --accent-color: #43b581;
    --background-color: #36393f;
    --card-background: #2f3136;
    --text-primary: #ffffff;
    --text-secondary: #b9bbbe;
    --border-color: #202225;
    --hover-color: #4f545c;
    
    /* 字体 */
    --font-primary: 'Helvetica Neue', Arial, sans-serif;
    
    /* 间距 */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-xxl: 48px;
    
    /* 圆角 */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
    --border-radius-full: 50%;
    
    /* 过渡效果 */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* 基础样式 */
body {
    font-family: var(--font-primary);
    background-color: var(--background-color);
    background-image: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)), url('beij.webp');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 导航栏样式 */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: transparent;
    padding: var(--spacing-md) var(--spacing-xl);
    border-bottom: none;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar-left .logo {
    display: flex;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    gap: var(--spacing-sm);
}

.navbar-left .logo img {
    height: 40px;
    width: auto;
    object-fit: contain;
}

.navbar-center {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: white;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-normal);
}

/* 下拉菜单样式 */
.dropdown {
    position: relative;
}

.dropdown-toggle {
    background: none;
    border: none;
    margin: 0;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    z-index: 1001;
    min-width: 120px;
    display: none;
}

.dropdown:hover .dropdown-menu {
    display: block;
}

.dropdown-item {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: white;
    text-decoration: none;
    font-size: 14px;
    cursor: pointer;
}

.dropdown-item:hover {
    background-color: var(--hover-color);
    color: var(--primary-color);
}

/* LOGO链接样式 */
.logo-link {
    text-decoration: none;
    display: inline-block;
}

.nav-link:hover {
    /* 移除悬浮时的背景框效果 */
    background-color: transparent;
    color: var(--text-primary);
}

.nav-link i {
    font-size: 18px;
}

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

.login-btn, .signup-btn {
    padding: var(--spacing-sm) var(--spacing-xl);
    border: none;
    border-radius: var(--border-radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

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

.login-btn:hover {
    background-color: var(--hover-color);
}

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

.signup-btn:hover {
    background-color: var(--primary-dark);
}

/* 语言切换样式 */
.language-switch {
    display: flex;
    background-color: var(--hover-color);
    border-radius: var(--border-radius-md);
    overflow: hidden;
}

.lang-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    border: none;
    background-color: transparent;
    color: var(--text-secondary);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.lang-btn:hover {
    background-color: var(--border-color);
    color: var(--text-primary);
}

.lang-btn.active {
    background-color: var(--primary-color);
    color: var(--text-primary);
}

/* 主内容区样式 */
.main-content {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-xxl) var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
    min-height: calc(100vh - 80px);
}

.content-center {
    text-align: center;
    max-width: 800px;
}

.content-center h1 {
    font-size: 48px;
    font-weight: bold;
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
}

.content-left p {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.5;
}

.cta-buttons {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
}

.download-btn, .browser-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--border-radius-md);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
    min-width: 180px;
    justify-content: center;
}

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

.download-btn:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(88, 97, 242, 0.3);
}

.browser-btn {
    background-color: var(--card-background);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.browser-btn:hover {
    background-color: var(--hover-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* 功能特性网格 */
.features-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
}

.feature {
    background-color: var(--card-background);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.feature:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
    border-color: var(--primary-color);
}

.feature i {
    font-size: 32px;
    color: var(--accent-color);
    margin-bottom: var(--spacing-md);
}

.feature h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.feature p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* 页脚样式 */
.footer {
    background-color: var(--card-background);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-xxl) var(--spacing-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
    margin-bottom: var(--spacing-xxl);
}

.footer-section h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
}

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

.footer-section ul li {
    margin-bottom: var(--spacing-sm);
}

.footer-section ul li a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    transition: color var(--transition-normal);
}

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

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: var(--hover-color);
    border-radius: var(--border-radius-full);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-normal);
}

.social-link:hover {
    background-color: var(--primary-color);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
    max-width: 1400px;
    margin: 0 auto;
}

.footer-bottom .logo {
    display: flex;
    align-items: center;
    font-size: 20px;
    font-weight: bold;
    color: var(--primary-color);
    gap: var(--spacing-sm);
}

.footer-bottom .logo i {
    font-size: 24px;
}

.footer-bottom p {
    font-size: 12px;
    color: var(--text-secondary);
}

/* 功能特性页面样式 */
.features-page {
    padding: 80px 20px;
    text-align: center;
    color: var(--text-primary);
}

.features-page h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.features-page p {
    font-size: 1.2rem;
    margin-bottom: 60px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    color: var(--text-secondary);
}

.features-grid-full {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
    margin-bottom: 60px;
}

.feature-card {
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 15px;
    padding: 40px 30px;
    transition: all 0.3s ease;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
    border-color: var(--primary-color);
}

.feature-card i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-card h2 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-secondary);
    max-width: none;
    margin: 0;
}

/* 视频展示区样式 */
.video-gallery {
    padding: 60px 20px;
    text-align: center;
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    margin: 40px 20px;
    backdrop-filter: blur(10px);
}

.video-gallery h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.video-gallery p {
    font-size: 1.2rem;
    margin-bottom: 40px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    color: var(--text-secondary);
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr); /* 两列布局 */
    gap: 30px;
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

.video-grid-new {
    display: flex;
    gap: 30px;
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
    align-items: flex-start;
}

.main-video-card {
    flex: 2;
    min-width: 0;
}

.main-video {
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
}

.side-videos {
    flex: 0.8; /* 缩小侧边视频容器的宽度比例 */
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.side-video {
    flex: 1;
    min-width: 0;
}

.side-video .video-card {
    border: none; /* 移除侧边视频卡片的边框 */
    box-shadow: none; /* 可选：移除阴影效果 */
    background-color: transparent; /* 可选：设置透明背景 */
    backdrop-filter: none; /* 可选：移除模糊效果 */
}

.side-video .video-container {
    padding-top: 85%; /* 调整为更紧凑的宽高比 */
}

.video-card {
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 15px;
    overflow: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
    border-color: var(--primary-color);
}

.video-container {
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    overflow: hidden;
}

.video-container iframe,
.video-container video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
    outline: none;
}

.video-info {
    padding: 20px;
    text-align: left;
}

.video-info h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.video-info p {
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-secondary);
    margin: 0;
    max-width: 100%;
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
        text-align: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .cta-buttons {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .navbar-center {
        display: none;
    }
    
    .navbar-right {
        gap: var(--spacing-sm);
    }
    
    .login-btn, .signup-btn {
        padding: var(--spacing-xs) var(--spacing-md);
        font-size: 12px;
    }
    
    .main-content {
        padding: var(--spacing-xl) var(--spacing-md);
    }
    
    .content-left h1 {
        font-size: 32px;
    }
    
    .content-left p {
        font-size: 16px;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .download-btn, .browser-btn {
        width: 100%;
        max-width: 300px;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: var(--spacing-lg);
        text-align: center;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: var(--spacing-md);
    }
    
    .navbar-right {
        gap: var(--spacing-xs);
    }
    
    .language-switch {
        display: none;
    }
    
    .content-left h1 {
        font-size: 24px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .social-links {
        justify-content: center;
    }
}

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

.main-content {
    animation: fadeInUp var(--transition-slow);
}

.feature {
    animation: fadeInUp var(--transition-slow) calc(var(--delay) * 0.1s);
}

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

::-webkit-scrollbar-track {
    background-color: var(--border-color);
}

::-webkit-scrollbar-thumb {
    background-color: var(--hover-color);
    border-radius: var(--border-radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background-color: var(--primary-color);
}