/* ============================================
   Navbar（按 REDESIGN_PLAN.md）
   - 固定导航 / 克制留白 / 细线分隔
   ============================================ */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-fixed);
  height: var(--navbar-height);
  background-color: var(--color-cream);
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition-base), box-shadow var(--transition-base);
}

.navbar.scrolled {
  background-color: rgba(255, 254, 249, 0.98);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.05);
}

.navbar-container {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--space-md);
}

/* ========== Brand ========== */
.navbar-brand {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  white-space: nowrap;
}

.brand-cn {
  font-family: var(--font-cn-heading);
  font-size: 20px;
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: var(--tracking-wide);
}

.brand-en {
  font-family: var(--font-en-display);
  font-size: 11px;
  color: var(--color-stone);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
}

/* ========== Nav ========== */
.navbar-nav {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0;
  padding: 0;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-cn-body);
  font-size: 15px;
  font-weight: 500;
  color: var(--color-secondary);
  text-decoration: none;
  padding: 10px 16px;
  position: relative;
  transition: color var(--transition-fast);
  cursor: pointer;
  background: transparent;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 16px;
  right: 16px;
  height: 1px;
  background-color: var(--color-primary);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition-slow);
}

.nav-link:hover::after,
.nav-link.active::after {
  transform: scaleX(1);
}

.nav-link.nav-button {
  border: none;
}

/* ========== Dropdown ========== */
.dropdown-toggle .dropdown-arrow {
  width: 6px;
  height: 6px;
  border-right: 1px solid currentColor;
  border-bottom: 1px solid currentColor;
  transform: rotate(45deg);
  margin-left: 2px;
  transition: transform var(--transition-fast);
}

.dropdown:hover .dropdown-toggle .dropdown-arrow,
.dropdown:focus-within .dropdown-toggle .dropdown-arrow {
  transform: rotate(225deg);
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + 14px);
  left: 0;
  min-width: 220px;
  list-style: none;
  margin: 0;
  padding: 10px 0;
  background-color: var(--color-cream);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
}

.dropdown:hover .dropdown-menu,
.dropdown:focus-within .dropdown-menu,
.dropdown.open .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu a {
  display: block;
  padding: 10px 18px;
  font-size: 14px;
  color: var(--color-secondary);
  transition: background-color var(--transition-fast), color var(--transition-fast), padding-left var(--transition-fast);
}

.dropdown-menu a:hover {
  background-color: var(--color-warm-ivory);
  color: var(--color-primary);
  padding-left: 22px;
}

/* ========== Tools ========== */
.navbar-tools {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ========== Mobile ========== */
.navbar-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  align-items: center;
  justify-content: center;
  gap: 6px;
  cursor: pointer;
  background-color: transparent;
}

.navbar-toggle span {
  display: block;
  width: 18px;
  height: 1px;
  background-color: var(--color-primary);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.navbar-toggle.active span:nth-child(1) {
  transform: translateY(3.5px) rotate(45deg);
}

.navbar-toggle.active span:nth-child(2) {
  transform: translateY(-3.5px) rotate(-45deg);
}

@media (max-width: 1024px) {
  .navbar-container {
    padding: 0 var(--space-md);
  }

  .navbar-toggle {
    display: inline-flex;
  }

  .navbar-nav {
    position: fixed;
    top: var(--navbar-height);
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-cream);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-xl) var(--space-md);
    gap: 0;
    transform: translateX(-100%);
    transition: transform var(--transition-slow);
    overflow-y: auto;
  }

  .navbar-nav.active {
    transform: translateX(0);
  }

  .nav-item {
    width: 100%;
  }

  .nav-link {
    width: 100%;
    justify-content: space-between;
    padding: 14px 10px;
  }

  .nav-link::after {
    left: 10px;
    right: 10px;
  }

  .dropdown-menu {
    position: static;
    min-width: 0;
    width: 100%;
    border: none;
    border-radius: 0;
    box-shadow: none;
    padding: 0;
    margin: 0 0 var(--space-sm);
    opacity: 1;
    visibility: visible;
    transform: none;
    display: none;
    background-color: transparent;
  }

  .dropdown.open .dropdown-menu {
    display: block;
  }

  .dropdown-menu a {
    padding: 10px 10px 10px 18px;
    border-left: 1px solid var(--color-divider);
    margin-left: 10px;
  }

  .dropdown-menu a:hover {
    background-color: transparent;
    padding-left: 22px;
  }
}

@media (max-width: 768px) {
  .brand-cn {
    font-size: 18px;
  }

  .navbar-tools .btn-lang {
    display: none;
  }
}