/* =============== 主题变量 =============== */
:root {
  --nav-bg: #97d7c9;
  --pill-bg: #e2b52a;
  --pill-bg-hover: #f0ca3a;
  --pill-text: #ffffff;
  --dropdown-bg: #fff3b0;
  --brand-bubble: rgba(255, 255, 255, .85);
}

body {
  padding-top: 76px;
}

/* =============== 顶部导航条 =============== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 18px;
  background-color: var(--nav-bg);

  /* 关键设置： */
  background-image: url(https://static.igem.wiki/teams/5550/pic/navgation/nav-bac-pic.webp);
  background-repeat: repeat-x;
  /* 只横向平铺 */
  background-size: auto 100%;
  /* 高度占满导航条，宽度按比例 */
  background-position: top center;
  /* 贴顶部，水平居中 */

  transition: padding .2s ease, box-shadow .2s ease;
  /* 如果是像素风格纹理，避免被浏览器插值变糊： */
  image-rendering: -webkit-optimize-contrast;
  image-rendering: pixelated;
}

.navbar.nav-scrolled {
  padding: 6px 18px;
  box-shadow: 0 6px 18px rgba(0, 0, 0, .08);
}

/* 品牌区（左） */
.navbar .navbar-brand {
  color: #1e6c60;
  text-decoration: none;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  line-height: 1;
}

.navbar .navbar-brand:first-of-type {
  background: var(--brand-bubble);
  padding: 8px 14px;
  border-radius: 20px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, .06);
}

.navbar .navbar-brand+.navbar-brand {
  background: var(--brand-bubble);
  padding: 6px 10px;
  border-radius: 20px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, .06);
}

.navbar img {
  height: 52px;
  width: auto;
  display: block;
}

/* —— 让整排菜单靠右 —— */
.navbar .navbar-nav {
  margin-left: auto;
  /* 核心：把 <ul> 推向右侧 */
  display: flex;
  align-items: center;
  gap: 14px;
  padding-left: 0;
  margin: 0;
  /* 清除 ul 默认内外边距 */
  list-style: none;
}

.navbar .navbar-nav>li::marker {
  content: none;
}

/* 一级菜单：金色胶囊 */
.navbar .nav-item {
  position: relative;
  list-style: none;
}

.navbar .nav-link {
  display: inline-block;
  padding: 10px 22px;
  background: var(--pill-bg);
  color: var(--pill-text);
  border-radius: 9999px;
  font-weight: 600;
  letter-spacing: .3px;
  white-space: nowrap;
  text-decoration: none;
  transition: transform .15s ease, box-shadow .15s ease, background .15s ease;
}

.navbar .nav-link:hover,
.navbar .nav-item.show>.nav-link {
  background: var(--pill-bg-hover);
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(226, 181, 42, .35);
}

/* 下拉菜单（动效 + 防闪闭） */
.dropdown-menu {
  position: absolute;
  top: calc(100% + 10px);
  left: 50%;
  transform: translateX(-50%) translateY(0) scale(0.98);
  min-width: 180px;
  background: var(--dropdown-bg);
  border: none;
  border-radius: 14px;
  padding: 8px;
  box-shadow: 0 18px 30px rgba(0, 0, 0, .12);

  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity .15s ease, visibility .15s ease, transform .15s ease;
}

/* 开启状态（由 .show 或 :hover 触发，二者任一即可） */
.nav-item.show>.dropdown-menu,
.nav-item:hover>.dropdown-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0) scale(1);
}

/* 小尖角 */
.dropdown-menu::before {
  content: "";
  position: absolute;
  top: -8px;
  left: 50%;
  transform: translateX(-50%) rotate(45deg);
  width: 14px;
  height: 14px;
  background: var(--dropdown-bg);
  border-radius: 3px;
  box-shadow: -2px -2px 4px rgba(0, 0, 0, .02);
}

/* 透明“桥接区”：接住从按钮到下拉的鼠标 */
.dropdown-menu::after {
  content: "";
  position: absolute;
  top: -10px;
  left: 0;
  right: 0;
  height: 10px;
}

/* 下拉项 */
.dropdown-item {
  display: block;
  padding: 5px 5px;
  text-align: center;
  border-radius: 10px;
  color: #5a4a00;
  text-decoration: none;
  font-weight: 600;
}

.dropdown-item:hover {
  background: rgba(0, 0, 0, .06);
}

/* 汉堡按钮（仅小屏显示） */
.navbar-toggler {
  margin-left: auto;
  border: none;
  background: transparent;
  cursor: pointer;
  width: 40px;
  height: 32px;
  display: none;
  position: relative;
}

.navbar-toggler .navbar-toggler-icon,
.navbar-toggler::before,
.navbar-toggler::after {
  content: "";
  position: absolute;
  left: 8px;
  right: 8px;
  height: 2px;
  background: #2b6d62;
  transition: transform .2s ease, opacity .2s ease;
}

.navbar-toggler .navbar-toggler-icon {
  top: 15px;
}

.navbar-toggler::before {
  top: 8px;
}

.navbar-toggler::after {
  top: 22px;
}

/* 折叠容器 */
.collapse {
  display: flex;
}

.collapse.show {
  display: block;
}

/* ====== 响应式（<=992px） ====== */
@media (max-width: 992px) {
  .navbar {
    padding: 8px 14px;
  }

  .navbar-toggler {
    display: block;
  }

  .collapse {
    display: none;
    width: 100%;
  }

  .navbar .navbar-nav {
    margin-left: 0;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    padding: 10px 0;
  }

  .nav-item {
    width: 100%;
  }

  .nav-link {
    display: block;
    text-align: center;
    width: 100%;
  }

  .dropdown-menu {
    position: static;
    left: auto;
    transform: none;
    box-shadow: none;
    margin-top: 6px;
  }

  .nav-item.show>.dropdown-menu,
  .nav-item:hover>.dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
  }

  /* 限制导航容器最大宽度并居中 */
  .collapse.show {
    max-width: 320px;
    /* 限制最大宽度限制 */
    margin-left: auto;
    margin-right: auto;
    padding-left: 10px;
    padding-right: 10px;
  }

  /* 限制下拉菜单宽度 */
  .dropdown-menu {
    max-width: 280px;
    margin-left: auto;
    margin-right: auto;
  }
}

/* 去掉下拉列表的小圆点 + 左缩进 */
.navbar .dropdown-menu,
.navbar .dropdown-menu>li {
  list-style: none !important;
  margin: 0;
  padding: 0;
}

.navbar .dropdown-menu>li::marker {
  content: "" !important;
  /* 保险：移除 ::marker */
}

/* 下拉项自身的内边距保持，用在 <a class="dropdown-item"> 上 */
.navbar .dropdown-menu .dropdown-item {
  display: block;
  padding: 10px 12px;
}

/* 把包含菜单的 collapse 整体推到导航条最右侧 */
.navbar .collapse {
  margin-left: auto;
}

/* 避免 <ul> 再次用 auto 挤位，保持 0 即可 */
.navbar .navbar-nav {
  margin-left: 0;
}

@media (max-width: 768px) {
  .navbar img[alt="LZU-China"] {
    display: none;
  }
}