/***** Header 基础 *****/
header {
  background-color: #cbcfd2;
  color: #fff;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/***** 顶层导航横排（保持你的原配置） *****/
nav ul {
  list-style: none;
  margin: 0;
  padding: 0;

  display: flex;
  align-items: center;
}

nav ul > li {
  margin: 0 15px;
  position: relative; /* 为绝对定位的下拉提供定位上下文 */
}

/* 链接与触发按钮视觉统一 */
nav ul li > a,
nav .dropdown-toggle {
  color: #5c5c5c;
  text-decoration: none;
  font-size: 18px;
  font-weight: bold;

  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

nav ul li > a:hover,
nav .dropdown-toggle:hover {
  color: #333;
  text-decoration: none;
}

nav .dropdown-toggle:focus-visible {
  outline: 2px solid #d1d5db;
  outline-offset: 2px;
}

nav .caret {
  font-size: 12px;
  line-height: 1;
  transform: translateY(1px);
}

/***** 下拉菜单样式 *****/
nav .dropdown-menu {
  /* 覆盖顶层 nav ul 的 flex 影响，强制竖排 + 隐藏 */
  display: none;

  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 180px;

  margin: 0;
  padding: 8px 0;
  list-style: none;

  background: #fff;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.08);
  z-index: 1000;
}

nav .dropdown-menu li {
  margin: 0; /* 不继承顶层 li 的左右外边距 */
}

nav .dropdown-menu a {
  display: block;
  padding: 10px 14px;
  text-decoration: none;
  color: #111;
  font-size: 16px;
  font-weight: normal;
  white-space: nowrap;
}

nav .dropdown-menu a:hover,
nav .dropdown-menu a:focus {
  background: #f3f4f6;
  color: #000;
  outline: none;
}

/* 展开态（由 JS 添加 .open） */
nav .dropdown.open > .dropdown-menu {
  display: block;
}

/* 桌面端 hover 也展开；移动端不依赖 hover
@media (hover:hover) {
  nav .dropdown:hover > .dropdown-menu {
    display: block;
  }
} */

/* 简单的移动端适配：允许换行 */
@media (max-width: 768px) {
  header { padding: 10px 16px; }
  nav ul { flex-wrap: wrap; gap: 10px 16px; }
}