:root {
    /* 颜色系统 */
    --color-primary: #9E2A2B; /* 北京红 */
    --color-secondary: #335C67; /* 长城青 */
    --color-accent: #E09F3E; /* 琉璃金 */
    --color-light: #FFF8F0; /* 宣纸白 */
    --color-dark: #2D3047; /* 墨黑 */
    
    /* 字体设置 */
    --font-family-sans: "Noto Sans SC", "Roboto", sans-serif;
    --font-family-serif: "Noto Serif SC", Georgia, serif;
    --font-size-base: 20px;
    --font-size-large: 28px;
    --font-size-h1: 48px;
    --font-size-h2: 36px;
    --font-size-h3: 28px;
    
    /* 间距设置 */
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 48px;
    
    /* 过渡效果 */
    --transition-default: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-sans);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-dark);
    background-color: var(--color-light);
    overflow-x: hidden;
}

/* 标题样式 */
h1, h2, h3, h4 {
    font-family: var(--font-family-serif);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
    line-height: 1.2;
}

h1 {
    font-size: var(--font-size-h1);
}

h2 {
    font-size: var(--font-size-h2);

}

h3 {
    font-size: var(--font-size-h3);
}

/* 段落样式 */
p {
    margin-bottom: var(--spacing-md);
}

.cn {
    display: inline;
}

.en {
    display: none;
}

/* 语言切换 */
.lang-en .cn {
    display: none;
}

.lang-en .en {
    display: inline;
}

/* 链接样式 */
a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition-default);
}

a:hover {
    color: var(--color-accent);
}

/* 按钮样式 */
.btn-primary {
    display: inline-block;
    background-color: var(--color-primary);
    color: white;
    padding: 12px 24px;
    border-radius: 4px;
    font-size: var(--font-size-base);
    font-weight: 600;
    text-align: center;
    transition: var(--transition-default);
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background-color: #722021;
    transform: translateY(-2px);
    color: white;
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 248, 240, 0.95);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 28px;
    font-weight: 700;
    color: var(--color-primary);
    font-family: var(--font-family-serif);
}

.main-nav ul {
    display: flex;
    list-style: none;
}

.main-nav li {
    margin-left: var(--spacing-lg);
}

.main-nav a {
    font-weight: 600;
    position: relative;
    padding: 8px 0;
}

.main-nav a.active {
    color: var(--color-primary);
}

.main-nav a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--color-primary);
}

.controls {
    display: flex;
    align-items: center;
}

.control-btn {
    background: none;
    border: none;
    font-size: 20px;
    color: var(--color-dark);
    margin-left: var(--spacing-md);
    cursor: pointer;
    transition: var(--transition-default);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.control-btn:hover {
    background-color: rgba(0, 0, 0, 0.1);
    color: var(--color-primary);
}

/* 移动端菜单 */
.mobile-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    height: 100vh;
    background-color: var(--color-light);
    z-index: 1100;
    padding: 80px 24px;
    transition: var(--transition-default);
    box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
}

.mobile-menu.active {
    right: 0;
}

.mobile-menu ul {
    list-style: none;
}

.mobile-menu li {
    margin-bottom: var(--spacing-lg);
}

.mobile-menu a {
    font-size: 24px;
    font-weight: 600;
    display: block;
    padding: 8px 0;
}

/* 主内容区样式 */
.main-content {
    margin-top: 80px;
    padding: var(--spacing-xl) 24px;
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
}

/* 页面头部 */
.page-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--color-primary);
}

.page-header p {
    font-size: 24px;
    color: var(--color-secondary);
}

/* 区块头部 */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    position: relative;
}

.section-header::after {
    content: '';
    display: block;
    width: 80px;
    height: 3px;
    background-color: var(--color-accent);
    margin: var(--spacing-md) auto 0;
}

/* 首页主视觉 */
.hero-section {
    position: relative;
    height: 100vh;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

.hero-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-video-container {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.8;
}

.hero-video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-content {
    position: relative;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: white;
    padding: 0 24px;
    background-color: rgba(0, 0, 0, 0.4);
}

.hero-content h1 {
    font-size: 64px;
    margin-bottom: var(--spacing-lg);
    color: white;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.hero-content p {
    font-size: 28px;
    margin-bottom: var(--spacing-xl);
    max-width: 800px;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

/* 概览区块 */
.overview-section {
    margin-bottom: var(--spacing-xl);
}

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

.overview-text {
    flex: 1;
}

.overview-stats {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
}

.stat-card {
    background-color: white;
    padding: var(--spacing-lg);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: var(--transition-default);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.stat-number {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.stat-label {
    font-size: 20px;
    color: var(--color-secondary);
}

/* 快速导航 */
.quick-nav {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.nav-card {
    height: 400px;
    border-radius: 8px;
    overflow: hidden;
    position: relative;
    transition: var(--transition-default);
}

.nav-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
}

.nav-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to bottom, rgba(0,0,0,0.1), rgba(0,0,0,0.8));
    z-index: 1;
}

.nav-card a {
    position: relative;
    z-index: 2;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    padding: var(--spacing-xl);
    color: white;
    text-decoration: none;
}

.nav-card h3 {
    color: white;
    font-size: 32px;
    margin-bottom: var(--spacing-sm);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.nav-card p {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-lg);
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

.nav-card .more-link {
    display: inline-block;
    font-size: 20px;
    font-weight: 600;
    color: white;
    text-decoration: underline;
    transition: var(--transition-default);
}

.nav-card .more-link:hover {
    transform: translateX(5px);
}

.nav-card a {
    background-size: cover;
    background-position: center;
}

/* 视频区块 */
.video-section {
    margin-bottom: var(--spacing-xl);
}

.video-container {
    max-width: 1200px;
    margin: 0 auto;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.city-video {
    width: 100%;
    height: auto;
}

/* 时间轴样式 */
.timeline-section {
    margin-bottom: var(--spacing-xl);
    position: relative;
}

.timeline-container {
    position: relative;
    padding: var(--spacing-lg) 0;
}

.timeline-track {
    position: relative;
    padding-left: var(--spacing-xl);
}

.timeline-track::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    width: 4px;
    background-color: var(--color-primary);
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-xl);
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition-default);
}

.timeline-item.animate-in {
    opacity: 1;
    transform: translateY(0);
}

.timeline-date {
    position: absolute;
    left: calc(-1 * var(--spacing-xl) - 120px);
    top: 0;
    width: 120px;
    font-weight: 700;
    color: var(--color-primary);
    text-align: right;
}

.timeline-content {
    background-color: white;
    padding: var(--spacing-lg);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: -12px;
    top: 24px;
    width: 24px;
    height: 24px;
    background-color: white;
    border: 4px solid var(--color-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 4px rgba(158, 42, 43, 0.1);
}

.timeline-image {
    width: 100%;
    max-width: 600px;
    height: auto;
    border-radius: 4px;
    margin-top: var(--spacing-md);
}

/* 建筑网格 */
.architecture-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.architecture-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: var(--transition-default);
    opacity: 0;
    transform: translateY(20px);
}

.architecture-card.animate-in {
    opacity: 1;
    transform: translateY(0);
}

.architecture-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.architecture-image {
    width: 100%;
    height: 300px;
    object-fit: cover;
}

.architecture-card h3,
.architecture-card p {
    padding: 0 var(--spacing-lg);
}

.architecture-card p {
    margin-bottom: var(--spacing-lg);
}

.architecture-card .more-link {
    display: inline-block;
    margin: 0 var(--spacing-lg) var(--spacing-lg);
    color: var(--color-primary);
    font-weight: 600;
    text-decoration: underline;
}

/* 传统艺术区块 */
.traditional-arts {
    margin-bottom: var(--spacing-xl);
}

.arts-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.art-item {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    opacity: 0;
    transform: translateX(-20px);
    transition: var(--transition-default);
}

.art-item:nth-child(even) {
    flex-direction: row-reverse;
    transform: translateX(20px);
}

.art-item.animate-in {
    opacity: 1;
    transform: translateX(0);
}

.art-image {
    width: 50%;
    height: 400px;
    object-fit: cover;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.art-content {
    width: 50%;
}

/* 字体控制工具 */
.font-controls {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 900;
    display: flex;
    gap: var(--spacing-sm);
}

.font-btn {
    background-color: var(--color-primary);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    font-size: 16px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    transition: var(--transition-default);
}

.font-btn:hover {
    background-color: #722021;
    transform: translateY(-2px);
}

/* 广告位样式 */
.ad-section {
    max-width: 1400px;
    margin: 0 auto var(--spacing-xl);
    padding: 0 24px;
}

.ad-container {
    background-color: rgba(0, 0, 0, 0.05);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-default);
}

.ad-container:hover {
    background-color: rgba(0, 0, 0, 0.08);
}

#ad-footer {
    height: 90px;
}

#ad-sidebar {
    width: 300px;
    height: 250px;
    float: right;
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

#ad-responsive {
    width: 100%;
    height: 250px;
}

.ad-placeholder {
    color: #888;
    font-size: 18px;
    text-align: center;
}

/* 页脚样式 */
.footer {
    background-color: var(--color-dark);
    color: white;
    padding: var(--spacing-xl) 24px;
    text-align: center;
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
}

.footer p {
    margin-bottom: 0;
    opacity: 0.8;
}

/* 滚动动画元素 */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: var(--transition-default);
}

.animate-on-scroll.animate-in {
    opacity: 1;
    transform: translateY(0);
}

/* 响应式设计 */
@media (max-width: 1199px) {
    .overview-content {
        flex-direction: column;
    }
    
    .overview-stats {
        width: 100%;
    }
    
    .art-image {
        height: 300px;
    }
}

@media (max-width: 991px) {
    .quick-nav {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .quick-nav .nav-card:nth-child(3) {
        grid-column: span 2;
    }
    
    .architecture-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .timeline-date {
        position: relative;
        left: 0;
        top: 0;
        width: 100%;
        text-align: left;
        margin-bottom: var(--spacing-sm);
    }
    
    .timeline-track {
        padding-left: var(--spacing-md);
    }
    
    .timeline-content::before {
        left: -8px;
    }
}

@media (max-width: 767px) {
    :root {
        --font-size-h1: 36px;
        --font-size-h2: 28px;
        --font-size-h3: 24px;
    }
    
    .main-nav {
        display: none;
    }
    
    .mobile-only {
        display: block;
    }
    
    .hero-content h1 {
        font-size: 48px;
    }
    
    .hero-content p {
        font-size: 22px;
    }
    
    .quick-nav {
        grid-template-columns: 1fr;
    }
    
    .quick-nav .nav-card:nth-child(3) {
        grid-column: span 1;
    }
    
    .architecture-grid {
        grid-template-columns: 1fr;
    }
    
    .art-item,
    .art-item:nth-child(even) {
        flex-direction: column;
        transform: translateY(20px);
    }
    
    .art-image,
    .art-content {
        width: 100%;
    }
    
    .art-image {
        height: 200px;
    }
    
    #ad-sidebar {
        width: 100%;
        float: none;
        margin-left: 0;
    }
    
    .nav-card {
        height: 300px;
    }
}

/* 辅助类 */
.mobile-only {
    display: none;
}

.clearfix::after {
    content: '';
    display: table;
    clear: both;
}

/* 为新添加的标题样式 */
.section-title {
    width: 100%;
    text-align: center;
    font-size: 2em;
    color: #333;
    margin-bottom: 30px;
    grid-column: 1 / -1; /* 跨越所有列 */
}

/* 通用卡片样式调整 */
.quick-nav {
    /* ... 您原有的 .quick-nav 样式 ... */
    /* 确保它是一个 grid 容器 */
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 50px 0;
}

.nav-card {
    /* ... 您原有的 .nav-card 样式 ... */
    /* 确保卡片样式适用于景点和美食 */
    height: auto; /* 允许卡片高度根据内容调整 */
    min-height: 250px; /* 设置一个最小高度 */
    display: flex;
    flex-direction: column;
    background-size: cover;
    background-position: center;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.nav-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0,0,0,0.2);
}

.nav-card a {
    display: flex;
    flex-direction: column;
    height: 100%;
    text-decoration: none;
    color: inherit;
}

/* 图片样式 */
.card-image {
    width: 100%;
    height: 150px; /* 固定图片高度 */
    object-fit: cover; /* 保持图片比例并裁剪 */
    display: block;
}

/* 内容区域样式 */
.card-content {
    flex-grow: 1;
    padding: 20px;
    background-color: rgba(255, 255, 255, 0.9); /* 半透明白色背景 */
    backdrop-filter: blur(10px); /* 毛玻璃效果 */
}

.card-content h3 {
    margin-top: 0;
    color: #333;
    font-size: 1.5em;
}

.card-content p {
    font-size: 0.9em;
    color: #666;
    line-height: 1.5;
    margin-bottom: 15px;
}

.card-content .more-link {
    display: inline-block;
    color: #c8102e; /* 北京红 */
    font-weight: bold;
    text-decoration: none;
    transition: color 0.3s ease;
}

.card-content .more-link:hover {
    color: #a00d24;
}

/* 特定卡片样式 (可选) */
.attraction-card {
    /* 可以为景点卡片添加特殊样式 */
}

.food-card {
    /* 可以为美食卡片添加特殊样式 */
}

/* 响应式调整 */
@media (max-width: 768px) {
    .quick-nav {
        grid-template-columns: 1fr; /* 在小屏幕上堆叠 */
    }
    
    .nav-card {
        min-height: auto;
    }
    
    .card-image {
        height: 200px; /* 在小屏幕上调整图片高度 */
    }
}