/* ============================================================================
   导航栏样式 - 固定导航栏 + 二级下拉菜单
   ============================================================================ */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(250, 249, 246, 0.95);
  backdrop-filter: blur(12px);
  box-shadow: 0 10px 30px rgba(13, 20, 30, 0.08);
  transition: all var(--transition-fast);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
  padding: 0 var(--spacing-lg);
  max-width: 1240px;
  margin: 0 auto;
}

/* Logo */
.navbar-logo {
  display: flex;
  align-items: center;
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transition: color var(--transition-fast);
}

.navbar-logo span {
  color: var(--color-secondary);
  margin-left: var(--spacing-sm);
  font-size: var(--font-size-base);
  letter-spacing: 0.2em;
}

.navbar-logo img {
  height: 40px;
  margin-right: var(--spacing-md);
}

/* 导航菜单 */
.navbar-menu {
  display: none;
  position: absolute;
  top: 80px;
  left: 0;
  right: 0;
  background: var(--color-white);
  flex-direction: column;
  padding: var(--spacing-md) 0;
  box-shadow: var(--shadow-md);
}

.navbar-menu.active {
  display: flex;
}

@media (min-width: 1024px) {
  .navbar-menu {
    display: flex;
    position: static;
    flex-direction: row;
    padding: 0;
    box-shadow: none;
    gap: var(--spacing-xl);
  }
}

/* 导航项 */
.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: var(--spacing-md) var(--spacing-xl);
  color: var(--color-neutral-800);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-base);
  letter-spacing: 0.04em;
  transition: all var(--transition-fast);
  border-bottom: 2px solid transparent;
}

@media (min-width: 1024px) {
  .nav-link {
    padding: var(--spacing-md) 0;
    border-bottom: 3px solid transparent;
    padding-bottom: calc(var(--spacing-md) - 3px);
  }
}

.nav-link:hover {
  color: var(--color-secondary);
  border-bottom-color: var(--color-secondary);
}

.nav-link.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-secondary);
}

/* 二级菜单 */
.submenu {
  display: none;
  position: static;
  flex-direction: column;
  background-color: var(--color-neutral-50);
  padding: 0;
  margin: 0;
  list-style: none;
  border-radius: var(--radius-lg);
}

@media (min-width: 1024px) {
  .submenu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    background-color: var(--color-white);
    box-shadow: 0 20px 60px rgba(23, 32, 52, 0.15);
    border-radius: var(--radius-lg);
    padding: var(--spacing-sm) 0;
    margin-top: var(--spacing-sm);
    border: 1px solid rgba(35, 48, 66, 0.08);
  }
}

.nav-item:hover > .submenu,
.nav-item:focus-within > .submenu {
  display: flex;
}

.submenu.active {
  display: flex;
}

.submenu-item {
  padding: 0;
}

.submenu-link {
  display: block;
  padding: var(--spacing-md) var(--spacing-xl);
  color: var(--color-neutral-800);
  text-decoration: none;
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
  margin-left: var(--spacing-lg);
}

@media (min-width: 1024px) {
  .submenu-link {
    border-left: none;
    margin-left: 0;
    padding: var(--spacing-md) var(--spacing-xl);
  }
  
  .submenu-link:hover {
    background: linear-gradient(90deg, rgba(212, 175, 55, 0.1), rgba(250, 249, 246, 0.5));
    color: var(--color-primary);
  }
}

.submenu-link:hover {
  color: var(--color-secondary);
  border-left-color: var(--color-secondary);
}

/* 菜单切换按钮（移动端） */
.navbar-toggle {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-md);
}

@media (min-width: 768px) {
  .navbar-toggle {
    display: none;
  }
}

.navbar-toggle span {
  display: block;
  width: 25px;
  height: 3px;
  background-color: var(--color-neutral-800);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.navbar-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.navbar-toggle.active span:nth-child(2) {
  opacity: 0;
}

.navbar-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(8px, -8px);
}

/* 右侧工具栏 */
.navbar-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.navbar-search {
  display: none;
  position: relative;
}

@media (min-width: 768px) {
  .navbar-search {
    display: flex;
  }
}

.navbar-search input {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  width: 200px;
  transition: all var(--transition-fast);
}

.navbar-search input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.navbar-cta {
  display: none;
}

@media (min-width: 768px) {
  .navbar-cta {
    display: inline-block;
  }
}

/* 页面内容顶部间距（为固定导航栏留出空间） */
main {
  margin-top: 70px;
}

/* 响应式调整 */
@media (max-width: 767px) {
  .navbar-container {
    height: 60px;
    padding: 0 var(--spacing-md);
  }
  
  main {
    margin-top: 60px;
  }
  
  .navbar-menu {
    top: 60px;
  }
}

/* 下拉菜单箭头 */
.nav-item > .nav-link::after {
  content: '';
  display: inline-block;
  width: 0;
  height: 0;
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
  border-top: 4px solid currentColor;
  margin-left: var(--spacing-sm);
  transition: transform var(--transition-fast);
}

.nav-item:hover > .nav-link::after {
  transform: rotate(180deg);
}

@media (max-width: 767px) {
  .nav-item > .nav-link::after {
    display: none;
  }
  
  .nav-item.has-submenu > .nav-link::after {
    content: '▼';
    display: inline;
    font-size: 10px;
    margin-left: var(--spacing-sm);
    transition: transform var(--transition-fast);
  }
  
  .nav-item.has-submenu.active > .nav-link::after {
    transform: rotate(180deg);
  }
}