/* ========================================
   导航栏与头部样式
   ======================================== */

/* 固定导航栏 */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(236, 239, 241, 0.92);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid transparent;
  box-shadow: 0 20px 60px rgba(38, 50, 56, 0.08);
  z-index: var(--z-fixed);
  transition: all var(--transition-fast);
}

header.scrolled {
  background: rgba(255, 255, 255, 0.98);
  border-bottom-color: var(--color-border);
  box-shadow: 0 25px 70px rgba(38, 50, 56, 0.12);
}

/* 导航栏容器 */
.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: var(--spacing-md) var(--spacing-xl);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  text-decoration: none;
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-secondary-dark);
  transition: all var(--transition-fast);
}

.logo:hover {
  color: var(--color-secondary);
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-secondary-dark), var(--color-primary));
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-lg);
  box-shadow: 0 10px 25px rgba(84, 110, 122, 0.35);
}

.logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
  gap: 4px;
}

.logo-text .company-name {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.02em;
}

.logo-text .company-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-normal);
}

/* 导航菜单 */
nav {
  flex: 1;
  margin: 0 var(--spacing-2xl);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 0;
  margin: 0;
  padding: 0;
}

.nav-item {
  position: relative;
}

.nav-link {
  position: relative;
  display: block;
  padding: var(--spacing-lg) var(--spacing-lg);
  color: var(--color-secondary-dark);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: var(--spacing-sm);
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-secondary-dark), var(--color-accent));
  border-radius: var(--radius-full);
  transform: translateX(-50%);
  transition: width var(--transition-fast);
}

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

.nav-link:hover::after,
.nav-link.active::after {
  width: 60%;
}

/* 下拉菜单 */
.dropdown {
  position: relative;
}

.dropdown-toggle::after {
  content: '▼';
  font-size: var(--font-size-xs);
  margin-left: var(--spacing-sm);
  color: var(--color-text-tertiary);
  transition: transform var(--transition-fast);
}

.dropdown:hover .dropdown-toggle::after {
  transform: rotate(180deg);
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  background: rgba(255, 255, 255, 0.95);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: 0 25px 60px rgba(38, 50, 56, 0.12);
  list-style: none;
  margin: 0;
  padding: var(--spacing-md) 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-fast);
  z-index: var(--z-dropdown);
  backdrop-filter: blur(12px);
}

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

.dropdown-item {
  display: block;
  padding: var(--spacing-md) var(--spacing-xl);
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}

.dropdown-item:hover {
  background: rgba(176, 190, 197, 0.15);
  color: var(--color-secondary-dark);
  border-left-color: var(--color-accent);
  padding-left: calc(var(--spacing-xl) + 6px);
}

/* 右侧操作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.search-box {
  display: flex;
  align-items: center;
  background-color: rgba(255, 255, 255, 0.45);
  border-radius: var(--radius-full);
  padding: var(--spacing-sm) var(--spacing-lg);
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 10px 25px rgba(84, 110, 122, 0.15);
  transition: all var(--transition-fast);
}

.search-box:focus-within {
  border-color: var(--color-secondary);
  box-shadow: 0 15px 30px rgba(84, 110, 122, 0.25);
}

.search-box input {
  background: transparent;
  border: none;
  outline: none;
  padding: 0;
  margin: 0;
  font-size: var(--font-size-sm);
  width: 150px;
}

.search-box input::placeholder {
  color: var(--color-text-tertiary);
}

.search-icon {
  color: var(--color-text-tertiary);
  cursor: pointer;
  transition: color var(--transition-fast);
}

.search-icon:hover {
  color: var(--color-accent-muted);
}

/* 汉堡菜单 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 6px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
}

.hamburger span {
  width: 24px;
  height: 3px;
  background-color: var(--color-secondary-dark);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

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

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

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* 移动端菜单 */
.mobile-menu {
  display: none;
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  background: rgba(236, 239, 241, 0.98);
  box-shadow: 0 25px 60px rgba(38, 50, 56, 0.12);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-fixed);
  max-height: calc(100vh - 60px);
  overflow-y: auto;
}

.mobile-menu.active {
  display: block;
}

.mobile-nav-item {
  display: block;
  padding: var(--spacing-lg) var(--spacing-xl);
  color: var(--color-text-primary);
  text-decoration: none;
  border-bottom: 1px solid var(--color-border);
  transition: all var(--transition-fast);
}

.mobile-nav-item:hover {
  background-color: rgba(176, 190, 197, 0.25);
  color: var(--color-secondary-dark);
  padding-left: calc(var(--spacing-xl) + 10px);
}

.mobile-submenu {
  display: none;
  background-color: var(--color-bg-secondary);
  padding: 0;
  list-style: none;
  margin: 0;
}

.mobile-submenu.active {
  display: block;
}

.mobile-submenu-item {
  display: block;
  padding: var(--spacing-md) var(--spacing-2xl);
  color: var(--color-text-secondary);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: all var(--transition-fast);
}

.mobile-submenu-item:hover {
  background-color: var(--color-white);
  color: var(--color-secondary-dark);
  border-left-color: var(--color-accent);
}

/* 响应式设计 */
@media (max-width: 768px) {
  .header-container {
    padding: var(--spacing-md) var(--spacing-md);
  }
  
  nav {
    display: none;
    margin: 0;
  }
  
  .hamburger {
    display: flex;
  }
  
  .header-actions {
    gap: var(--spacing-md);
  }
  
  .search-box {
    display: none;
  }
  
  .logo-text .company-desc {
    display: none;
  }
  
  .logo-text .company-name {
    font-size: var(--font-size-base);
  }
  
  .logo {
    font-size: var(--font-size-base);
  }
  
  .logo-icon {
    width: 32px;
    height: 32px;
    font-size: var(--font-size-base);
  }
}

/* 页面顶部空间预留 */
body {
  padding-top: 80px;
}

@media (max-width: 768px) {
  body {
    padding-top: 64px;
  }
}