/* =========================================
   1. RESET & BASE (基础重置)
   ========================================= */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: #333; /* 正文深灰 */
  background: #fff;
  /* 
     关键设置：防止固定Header遮挡内容
     桌面端 Header 比较高 (Logo+Nav)，预留 130px
     移动端在 Media Query 中会重置为 60px
  */
  padding-top: 130px; 
}

a {
  text-decoration: none;
  color: inherit;
  transition: color 0.3s ease;
}

ul {
  list-style: none;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: 6px;
}

/* =========================================
   2. HEADER STRUCTURE (头部通用结构)
   ========================================= */
.site-header {
  background: #ffffff; /* 纯白背景 */
  color: #000000;      /* 纯黑文字 */
  width: 100%;
  position: fixed;     /* 固定顶部 */
  top: 0;
  left: 0;
  z-index: 1000;
  border-bottom: 1px solid #f0f0f0; /* 极浅的分割线 */
  box-shadow: 0 4px 12px rgba(0,0,0,0.03); /* 高级感的微阴影 */
  transition: all 0.3s ease;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 5%;
  position: relative;
  height: 100%;
}

/* LOGO 通用样式 */
.logo {
  font-size: 1.8rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #000;
  z-index: 1002;
  text-align: center;
}

.logo a:hover {
  opacity: 0.7; /* Logo 悬停微效 */
}

/* =========================================
   3. DESKTOP NAVIGATION (屏幕 > 768px)
   ========================================= */
@media (min-width: 769px) {
  /* 隐藏移动端组件 */
  .mobile-toggle {
    display: none;
  }

  /* 桌面端布局：垂直排列 (Logo 在上，菜单在下) */
  .site-header {
    height: auto; /* 高度自适应内容 */
    min-height: 120px;
  }

  .header-inner {
    display: flex;
    flex-direction: column;
    align-items: center; /* 水平居中 */
    justify-content: center;
    padding-top: 15px;
  }

  .logo {
    margin-bottom: 15px; /* Logo 与菜单的间距 */
  }

  .nav-list {
    display: flex;
    gap: 35px; /* 菜单项间距 */
    align-items: center;
    padding-bottom: 15px;
  }

  .nav-list > li {
    position: relative;
    padding: 10px 0; /* 增加 hover 区域 */
  }

  /* 导航链接样式 */
  .nav-link, 
  .dropdown-header {
    cursor: pointer;
    color: #444;
    font-weight: 600;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 6px;
  }

  /* 悬停高亮色：品牌橙 */
  .nav-link:hover, 
  .dropdown-header:hover,
  .nav-list > li:hover .nav-link,
  .nav-list > li:hover .dropdown-header {
    color: #ff5500;
  }

  /* 桌面端小箭头 */
  .arrow {
    display: inline-block;
    width: 6px;
    height: 6px;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
    transform: rotate(45deg);
    margin-bottom: 2px;
    transition: transform 0.3s;
  }

  /* 悬停旋转箭头 */
  .has-dropdown:hover .arrow {
    transform: rotate(225deg);
  }

  /* 下拉菜单 (悬停显示) */
  .dropdown-menu {
    display: block; /* 使用 opacity 控制显示，利于动画 */
    visibility: hidden;
    opacity: 0;
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(15px); /* 初始位移 */
    background: #ffffff;
    min-width: 240px;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.12);
    padding: 10px 0;
    transition: all 0.3s ease;
    z-index: 1100;
    border: 1px solid #eee;
  }

  /* 触发下拉 */
  .has-dropdown:hover .dropdown-menu {
    visibility: visible;
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }

  /* 增加一个透明桥梁，防止鼠标移向下拉菜单时断开 */
  .dropdown-menu::before {
    content: '';
    position: absolute;
    top: -20px;
    left: 0;
    width: 100%;
    height: 20px;
  }

  .dropdown-menu a {
    display: block;
    padding: 12px 25px;
    color: #555;
    font-size: 0.9rem;
    transition: background 0.2s, color 0.2s;
  }

  .dropdown-menu a:hover {
    background: #fff5f0; /* 浅橙色背景 */
    color: #ff5500;
  }
}

/* =========================================
   4. MOBILE NAVIGATION (屏幕 <= 768px)
   ========================================= */
@media (max-width: 768px) {
  /* 重置 Body Padding */
  body {
    padding-top: 60px;
  }

  .site-header {
    height: 60px;
  }

  .header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
  }

  /* LOGO 移动端绝对居中 */
  .logo {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.2rem; /* 稍微缩小 */
    margin: 0;
    width: auto;
    white-space: nowrap;
  }

  /* 汉堡按钮 (左侧) */
  .mobile-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start; /* 左对齐 */
    width: 30px;
    height: 30px;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: 1001;
    padding: 0;
  }

  .bar {
    display: block;
    width: 22px;
    height: 2px;
    background: #000; /* 黑色线条 */
    margin: 2.5px 0;
    transition: all 0.3s ease-in-out;
    border-radius: 2px;
  }

  /* 汉堡按钮变为 X 动画 */
  .mobile-toggle.active .bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .mobile-toggle.active .bar:nth-child(2) {
    opacity: 0;
    width: 0;
  }
  .mobile-toggle.active .bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  /* 移动端菜单容器 (侧边滑出) */
  .main-nav {
    position: fixed;
    top: 60px;
    left: 0;
    width: 100%;
    height: calc(100vh - 60px);
    background: #ffffff;
    overflow-y: auto;
    transform: translateX(-100%); /* 默认隐藏 */
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-top: 1px solid #f0f0f0;
    padding-bottom: 50px; /* 底部留白 */
  }

  .main-nav.nav-open {
    transform: translateX(0); /* 滑入 */
  }

  .nav-list {
    padding: 10px 20px;
  }

  .nav-list > li {
    border-bottom: 1px solid #f9f9f9;
  }

  /* 移动端链接样式 */
  .nav-link, 
  .dropdown-header {
    padding: 18px 5px;
    font-size: 1.05rem;
    color: #222;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    font-weight: 500;
  }

  /* 移动端箭头 */
  .arrow {
    border: solid #aaa;
    border-width: 0 2px 2px 0;
    padding: 3px;
    transform: rotate(45deg);
    margin-right: 5px;
    transition: transform 0.3s;
  }

  /* 展开状态样式 */
  .has-dropdown.active .arrow {
    transform: rotate(225deg);
    border-color: #ff5500;
  }
  .has-dropdown.active .nav-label {
    color: #ff5500;
    font-weight: 600;
  }

  /* 移动端子菜单 (手风琴) */
  .dropdown-menu {
    display: none; /* 默认不占位 */
    background: #f8f8f8; /* 浅灰背景区分 */
    margin: 0 -20px; /* 撑满屏幕宽度 */
    padding: 5px 0;
  }

  /* JS 添加 active 后显示 */
  .has-dropdown.active .dropdown-menu {
    display: block;
    animation: fadeIn 0.3s ease;
  }

  .dropdown-menu a {
    display: block;
    padding: 14px 30px 14px 40px; /* 左侧缩进 */
    color: #555;
    font-size: 0.95rem;
    border-bottom: 1px solid #eee;
  }

  .dropdown-menu a:hover {
    color: #ff5500;
    background: #fff;
  }
}

/* =========================================
   5. MAIN CONTENT STYLING (页面内容)
   ========================================= */
main {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 0;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: #111;
  line-height: 1.2;
}

h2 {
  font-size: 1.8rem;
  margin: 2.5rem 0 1rem;
  color: #111;
  position: relative;
  display: inline-block;
}

/* H2 下划线装饰 */
h2::after {
  content: '';
  display: block;
  width: 40px;
  height: 3px;
  background: #ff5500;
  margin-top: 8px;
}

p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  color: #555;
  line-height: 1.7;
}

/* 视频与地图容器 */
.video-wrapper,
.map-wrapper {
  margin: 2rem 0;
  position: relative;
  width: 100%;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

iframe {
  display: block;
  width: 100%;
}

/* =========================================
   6. FAQ & DETAILS (折叠问答)
   ========================================= */
details {
  margin: 1rem 0;
  background: #fff;
  border: 1px solid #eee;
  border-radius: 6px;
  overflow: hidden;
  transition: all 0.3s;
}

details[open] {
  border-color: #ff5500;
  box-shadow: 0 4px 10px rgba(255, 85, 0, 0.1);
}

summary {
  padding: 1.2rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none; /* 隐藏默认箭头 */
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #fdfdfd;
}

summary:hover {
  background: #f5f5f5;
  color: #ff5500;
}

/* 自定义 Summary 加号图标 */
summary::after {
  content: '+';
  font-size: 1.4rem;
  font-weight: 300;
  color: #999;
}

details[open] summary::after {
  content: '-';
  color: #ff5500;
}

details p {
  padding: 1.2rem;
  margin: 0;
  background: #fff;
  border-top: 1px solid #f0f0f0;
  color: #666;
}

/* =========================================
   7. FOOTER (页脚)
   ========================================= */
footer {
  background: #111;
  color: #aaa;
  padding: 4rem 5% 2rem;
  margin-top: 5rem;
  font-size: 0.95rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 3rem;
  max-width: 1200px;
  margin: 0 auto;
}

footer h3 {
  color: #fff;
  margin-bottom: 1.5rem;
  font-size: 1.2rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

footer a {
  color: #aaa;
  display: inline-block;
  margin-bottom: 8px;
}

footer a:hover {
  color: #ff5500;
  text-decoration: none;
}

.copyright {
  margin-top: 4rem;
  text-align: center;
  font-size: 0.85rem;
  color: #555;
  border-top: 1px solid #222;
  padding-top: 2rem;
}

/* =========================================
   8. UTILITIES & ANIMATIONS
   ========================================= */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 针对小屏幕的排版调整 */
@media (max-width: 600px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  main { width: 92%; }
}