/* ========== 1. 基础重置与全局变量 ========== */
    :root {
      --nav-height: 64px;
      --primary-color: #1890ff;
      --text-main: #333;
      --text-desc: #666;
      --bg-light: #fafafa;
      --border-color: #eee;
    }

    * { box-sizing: border-box; margin: 0; padding: 0; }
    body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; }
    ul { list-style: none; }
    a { text-decoration: none; color: inherit; -webkit-tap-highlight-color: transparent; }

    /* ========== 2. 导航栏外层 ========== */
    .landing-nav {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: #fff;
      border-bottom: 1px solid var(--border-color);
      height: var(--nav-height);
    }

    .landing-nav__inner {
      margin: 0 auto;
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
      padding: 0 20px;
    }

    .landing-nav__left { display: flex; align-items: center; height: 100%; }

    /* ========== 3. Logo 区域 ========== */
    .landing-nav__brand { 
      display: flex; 
      align-items: center; 
      gap: 8px; 
      margin-right: 32px;
      flex-shrink: 0;
    }
    .landing-nav__logo { height: 50px; width: auto; }
    .landing-nav__name { font-size: 18px; font-weight: bold; color: var(--text-main); }

    /* ========== 4. 手机端汉堡按钮 (默认隐藏) ========== */
    .menu-toggle {
      display: none;
      flex-direction: column;
      justify-content: center;
      gap: 5px;
      width: 30px;
      height: var(--nav-height);
      cursor: pointer;
      margin-right: 15px;
    }
    .menu-toggle span {
      display: block;
      width: 22px;
      height: 2px;
      background: var(--text-main);
      transition: 0.3s;
      border-radius: 2px;
    }
    /* 激活态动画 */
    .menu-toggle.is-active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
    .menu-toggle.is-active span:nth-child(2) { opacity: 0; }
    .menu-toggle.is-active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

    /* ========== 5. 导航菜单逻辑 (PC & Mobile) ========== */
    .landing-nav__menu { display: flex; align-items: center; gap: 4px; }
    .landing-nav__menu > li > a {
      padding: 8px 16px;
      font-size: 15px;
      font-weight: 500;
      color: var(--text-main);
      display: flex;
      align-items: center;
      gap: 4px;
      border-radius: 6px;
      transition: background 0.2s;
    }

    /* PC 端 Hover */
    @media (min-width: 992px) {
      .landing-nav__menu > li > a:hover { background: var(--bg-light); }
      .landing-nav__dropdown { position: relative; height: var(--nav-height); display: flex; align-items: center; }
      
      /* PC 端 Mega Menu 显示 */
      .mega-menu {
        position: absolute;
        top: var(--nav-height);
        left: 50%;
        transform: translateX(-50%) translateY(10px);
        background: #fff;
        border-radius: 12px;
        box-shadow: 0 10px 40px rgba(0,0,0,0.1);
        display: flex;
        opacity: 0;
        visibility: hidden;
        transition: all 0.25s ease;
        padding: 24px;
        border: 1px solid var(--border-color);
      }
      .landing-nav__dropdown:hover .mega-menu {
        opacity: 1;
        visibility: visible;
        transform: translateX(-50%) translateY(0);
      }
      .landing-nav__dropdown:hover .landing-nav__arrow { transform: rotate(180deg); }
    }

    /* ========== 6. Mega Menu 内容样式 ========== */
    .mega-menu__preview { width: 280px; padding-right: 24px; border-right: 1px solid var(--border-color); }
    .mega-menu__screenshot img { width: 100%; border-radius: 8px; margin-bottom: 12px; }
    .mega-menu__preview-desc { font-size: 13px; color: var(--text-desc); line-height: 1.6; margin-bottom: 16px; }
    .mega-menu__actions { display: flex; flex-direction: column; gap: 8px; }
    .mega-menu__download {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 8px 12px;
      background: var(--primary-color);
      color: #fff;
      border-radius: 6px;
      font-size: 13px;
    }
    .mega-menu__download--secondary { background: #f0f2f5; color: var(--text-main); }

    .mega-menu__platforms { flex: 1; }
    .mega-menu__title { font-size: 12px; color: #999; margin-bottom: 16px; text-transform: uppercase; }
    .mega-menu__grid { display: grid; grid-template-columns: repeat(1, 1fr); gap: 12px; min-width: 200px; }
    
    .mega-menu__item {
      display: flex;
      align-items: center;
      gap: 10px;
      padding: 8px;
      border-radius: 8px;
      transition: background 0.2s;
    }
    .mega-menu__item:hover { background: var(--bg-light); }
    .mega-menu__icon-img { width: 24px; height: 24px; object-fit: contain; }
    
    .mega-menu__item-name { font-size: 14px;
    font-weight: 600;
    color: var(--gray-heading);
    display: inline-flex;
    align-items: center;
    gap: 4px;}
    
    .mega-menu__item-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

    .mega-menu__item-desc { font-size: 12px; color: #999; }

    /* AI 图标特定样式 */
    .mega-menu__platform-icon {
      width: 32px; height: 32px;
      display: flex; align-items: center; justify-content: center;
      border-radius: 6px; background: #e6f7ff; color: var(--primary-color);
    }

    /* ========== 7. 响应式 - 手机端 (Mobile) ========== */
    @media (max-width: 991px) {
      .menu-toggle { display: flex; }
      
      .landing-nav__menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        height: calc(100vh - var(--nav-height));
        background: #fff;
        flex-direction: column;
        align-items: stretch;
        padding: 0;
        gap: 0;
        transform: translateX(-100%);
        transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        overflow-y: auto;
      }

      .landing-nav__menu.is-active { transform: translateX(0); }

      .landing-nav__menu > li { border-bottom: 1px solid #f5f5f5; }
      .landing-nav__menu > li > a {
        padding: 18px 20px;
        font-size: 16px;
        justify-content: space-between;
        border-radius: 0;
      }

      /* 手机端二级菜单转为手风琴 */
      .mega-menu {
        display: block;
        max-height: 0;
        overflow: hidden;
        padding: 0 !important;
        border: none !important;
        box-shadow: none !important;
        background: #fafafa;
        transition: max-height 0.3s ease-out;
      }

      .landing-nav__dropdown.is-open .mega-menu {
        max-height: 100vh; /* 动态展开内容 */
      }

      .landing-nav__dropdown.is-open .landing-nav__arrow {
        transform: rotate(180deg);
      }

      /* 手机端隐藏预览图，优化路径 */
      .mega-menu__preview { display: none; }
      .mega-menu__platforms { padding: 15px 20px; }
      .mega-menu__grid { grid-template-columns: 1fr; min-width: 0; }
      
      .mega-menu__item { padding: 12px 0; border-bottom: 1px solid #f0f0f0; }
      .mega-menu__item:active { background: #eee; } /* 移动端点击反馈 */
    }

.landing-nav__login-btn {
  /* 解决换行问题的关键 */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  white-space: nowrap;      /* 强制文字在一行显示，不换行 */
  
  /* 尺寸与间距优化 */
  padding: 8px 10px;        /* 增加左右内边距，让按钮更丰满 */
  min-width: 50px;          /* 设置最小宽度，防止被挤压 */
  height: 36px;             /* 固定高度或使用 line-height */
  
  /* 样式部分 */
  background: var(--primary-color);
  color: #fff;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  
  /* 移动端点击体验 */
  transition: all 0.2s;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

/* 鼠标悬停效果 */
.landing-nav__login-btn:hover {
  opacity: 0.9;
  color: #fff;
}

/* 如果是在手机端，确保它所属的容器没有被 flex-shrink 挤扁 */
.landing-nav__right {
  display: flex;
  align-items: center;
  flex-shrink: 0;           /* 防止右侧按钮区域被左侧菜单挤压 */
}

.landing-nav__arrow { transition: transform 0.2s; }
    
    
    /* ========== 手机端布局 (991px 以下) ========== */
@media (max-width: 991px) {
  .landing-nav__inner {
    position: relative;   /* 为 Logo 居中提供定位参考 */
    justify-content: space-between;
  }

  .landing-nav__brand {
    /* 绝对定位实现视觉水平居中 */
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    margin-right: 0;
  }
  
  /* 确保 Logo 在小屏手机上不会太大挤到按钮 */
  img.landing-nav__logo {
    height: 40px; /* 手机端建议稍微缩小，若坚持50px可删掉此行 */
  }
}



/* ========== 简单下拉菜单基础样式 ========== */

/* 默认隐藏下拉列表 */
.simple-dropdown {
  list-style: none;
  padding: 0;
  margin: 0;
  background: #fff;
}

/* PC 端样式 (992px 以上) */
@media (min-width: 992px) {
  .simple-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 160px; /* 设置一个合适的宽度 */
    background: #ffffff;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid #eee;
    padding: 8px 0;
    
    /* 隐藏动画 */
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.2s ease;
    z-index: 100;
  }

  /* Hover 显示 */
  .landing-nav__dropdown:hover .simple-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .simple-dropdown li a {
    display: block;
    padding: 10px 20px;
    font-size: 14px;
    color: #333;
    transition: all 0.2s;
  }

  .simple-dropdown li a:hover {
    background-color: #f5f5f5;
    color: var(--primary-color);
  }
}

/* 移动端样式 (991px 以下) */
@media (max-width: 991px) {
  .simple-dropdown {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background: #fafafa; /* 稍微深一点的背景色区分层级 */
  }

  /* 配合你之前的 JS 逻辑，点击父级添加 .is-open 类 */
  .landing-nav__dropdown.is-open .simple-dropdown {
    max-height: 300px; /* 足够容纳三个 li 的高度 */
    padding: 5px 0;
  }

  .simple-dropdown li a {
    display: block;
    padding: 12px 30px; /* 增加左缩进，体现层级感 */
    font-size: 15px;
    color: #555;
    border-bottom: 1px solid #f0f0f0;
  }
  
  .simple-dropdown li:last-child a {
    border-bottom: none;
  }
}