/* ============================================================
   顶部导航栏 · header.css
   类名规范：site-header / site-nav / site-nav__* 
   ============================================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  transition: background .35s, box-shadow .35s, backdrop-filter .35s;
  background: transparent;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  box-shadow: none;
}

.site-nav {
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px
}

/* 取消 Bootstrap .container 遗留 clearfix 伪元素（导航用 flex，不需要） */
.container.site-nav::before,
.container.site-nav::after {
  display: none;
  content: none;
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 11px;
  font-family: var(--display);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -.02em;
  color: #fff;
  transition: color .3s;
}

.site-header.scrolled .site-brand {
  color: var(--text)
}

.site-brand img {
  max-height: 36px
}

.site-brand__logo {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  flex: none;
  object-fit: contain;
  display: block
}

.site-brand small {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .22em;
  color: var(--cyan);
  font-weight: 500;
  display: block;
  line-height: 1
}

.site-nav__menu {
  display: flex;
  gap: 2px;
  align-items: center;
  flex: 1;
  justify-content: center
}

.site-nav__menu>li {
  position: relative
}

.site-nav__menu>li>a {
  display: block;
  font-size: 14.5px;
  font-weight: 500;
  color: rgba(255, 255, 255, .78);
  padding: 9px 16px;
  border-radius: 0;
  transition: color .22s;
  cursor: pointer;
  position: relative;
}

.site-nav__menu>li>a::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 4px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--brand), var(--cyan));
  transform: scaleX(0);
  transform-origin: center;
  transition: transform .28s cubic-bezier(.4, 0, .2, 1);
}

.site-nav__menu>li>a:hover,
.site-nav__menu>li.active>a {
  color: #fff;
  background: none;
}

.site-nav__menu>li>a:hover::after,
.site-nav__menu>li.active>a::after {
  transform: scaleX(1);
}

.site-header.scrolled {
  background: rgba(255, 255, 255, .88);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: var(--shadow-sm);
}

.site-header.scrolled .site-nav__menu>li>a {
  color: var(--text-2);
}

.site-header.scrolled .site-nav__menu>li>a:hover,
.site-header.scrolled .site-nav__menu>li.active>a {
  color: var(--brand);
  background: none;
}

.site-nav__submenu {
  position: absolute;
  top: calc(100% + 12px);
  left: 50%;
  transform: translateX(-50%) translateY(6px) scale(.97);
  width: max-content;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow-lg);
  padding: 8px;
  opacity: 0;
  visibility: hidden;
  transition: opacity .22s, transform .22s, visibility .22s;
}

.site-nav__menu>li:hover .site-nav__submenu {
  opacity: 1;
  visibility: visible;
 
}

.site-nav__submenu a {
  display: block;
  padding: 11px 14px;
  border-radius: 10px;
  transition: background .16s;
  position: relative;
}

.site-nav__submenu a::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 50%;
  width: 3px;
  height: 0;
  border-radius: 2px;
  background: var(--brand);
  transform: translateY(-50%);
  transition: height .16s;
}

.site-nav__submenu a:hover,
.site-nav__submenu a.active {
  background: var(--surface-2);
}

.site-nav__submenu a:hover::before,
.site-nav__submenu a.active::before {
  height: 55%;
}

.site-nav__submenu a span {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
}

.site-nav__actions {
  display: flex;
  align-items: center;
  gap: 12px
}

.site-header.scrolled .btn-ghost,
.site-header.scrolled .btn-ghost:focus,
.site-header.scrolled .btn-ghost:active,
.site-header.scrolled .btn-ghost.active {
  color: var(--text) !important;
  border-color: var(--border-2) !important;
  background: transparent !important;
  box-shadow: none !important;
}

.site-header.scrolled .btn-ghost:hover {
  background: var(--surface-2) !important;
  color: var(--brand) !important;
  border-color: var(--brand) !important;
}

.site-nav__toggle {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: rgba(255, 255, 255, .1);
  border: 0;
  color: #fff;
  cursor: pointer;
  place-items: center;
  transition: background .2s;
}

.site-header.scrolled .site-nav__toggle {
  background: var(--surface-2);
  color: var(--text)
}

@media(max-width:760px) {

  .site-header {
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }

  body.nav-open .site-header {
    z-index: 80;
  }

  .site-nav__actions .btn-ghost,
  .site-nav__actions .btn-primary {
    display: none
  }

  .site-nav__toggle {
    display: grid
  }

  .site-nav__menu {
    display: none;
    flex: none;
  }

  .site-nav__menu.open {
    display: flex;
    position: fixed;
    top: 80px;
    left: 12px;
    right: 12px;
    bottom: auto;
    max-height: min(72vh, 520px);
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    background: var(--surface);
    padding: 6px 8px 12px;
    gap: 2px;
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    z-index: 90;
    overflow-x: hidden;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    margin: 0;
    list-style: none;
  }

  .site-nav__menu.open > li {
    flex: none;
  }

  .site-nav__menu.open > li > a {
    color: var(--text);
    text-align: left;
    border-radius: 10px;
    padding: 12px 14px;
    font-size: 15px;
    font-weight: 500;
    transition: background .18s, color .18s;
  }

  .site-nav__menu.open > li > a::after {
    display: none;
  }

  .site-nav__menu.open > li.has-drop > a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
  }

  .site-nav__menu.open > li.has-drop > a::before {
    content: "";
    order: 2;
    width: 8px;
    height: 8px;
    margin-left: 12px;
    border-right: 2px solid var(--text-3);
    border-bottom: 2px solid var(--text-3);
    transform: rotate(45deg);
    transition: transform .28s ease;
    flex: none;
  }

  .site-nav__menu.open > li.has-drop.is-open > a::before {
    transform: rotate(-135deg);
    margin-top: 4px;
  }

  .site-nav__menu.open > li > a:hover,
  .site-nav__menu.open > li.active > a,
  .site-nav__menu.open > li.has-drop.is-open > a {
    background: var(--surface-2);
    color: var(--brand);
  }

  .site-nav__menu.open .site-nav__submenu {
    display: block;
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    box-shadow: none;
    border: 0;
    background: transparent;
    min-width: 0;
    width: 100%;
    max-height: 0;
    overflow: hidden;
    padding: 0 8px;
    transition: max-height .28s ease, padding .28s ease;
  }

  .site-nav__menu.open > li.is-open > .site-nav__submenu {
    max-height: 320px;
    padding: 2px 8px 10px;
  }

  .site-nav__menu.open .site-nav__submenu a {
    padding: 11px 14px;
    border-radius: 10px;
    margin-bottom: 2px;
  }

  .site-nav__menu.open .site-nav__submenu a span {
    font-size: 14px;
    font-weight: 600;
    white-space: normal;
  }

  .site-nav__menu.open .site-nav__submenu a:hover,
  .site-nav__menu.open .site-nav__submenu a.active {
    background: var(--surface-2);
  }

  .site-nav__menu.open .site-nav__submenu a:hover::before,
  .site-nav__menu.open .site-nav__submenu a.active::before {
    height: 55%;
  }

  .site-nav__menu.open .site-nav__mobile-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 8px;
    padding: 12px 6px 4px;
    border-top: 1px solid var(--border);
  }

  .site-nav__menu.open .site-nav__mobile-actions .btn {
    width: 100%;
    justify-content: center;
    display: inline-flex;
  }

  .site-nav__menu.open .site-nav__mobile-actions .btn-ghost {
    color: var(--text) !important;
    border-color: var(--border-2) !important;
    background: var(--surface) !important;
  }

  .site-nav__menu.open .site-nav__mobile-actions .btn-ghost:hover {
    color: var(--brand) !important;
    border-color: var(--brand) !important;
    background: var(--surface-2) !important;
  }
}

body.nav-open {
  overflow: hidden;
}

body.nav-open::before {
  content: "";
  position: fixed;
  inset: 0;
  background: rgba(var(--ink-rgb), .28);
  z-index: 70;
}

.site-nav__mobile-actions {
  display: none;
}