/* ========================================
   页面布局样式 - 固定导航栏和页面结构
   ======================================== */

/* ========== 导航栏 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid rgba(3, 105, 161, 0.08);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(18px);
  transition: all var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
  background: rgba(255, 255, 255, 0.98);
  border-bottom-color: rgba(3, 105, 161, 0.15);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--spacing-md) var(--container-padding);
  height: 70px;
}

.navbar-brand {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-sm);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.navbar-brand:hover {
  color: var(--color-primary-dark);
}
.navbar-logo {
  height: 40px;
  width: auto;
}
.navbar-brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.navbar-brand-main {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  white-space: nowrap;
}
.navbar-brand-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-light);
  font-weight: var(--font-weight-medium);
}
.navbar-brand-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-light);
  font-weight: var(--font-weight-normal);
}

/* 导航菜单 */
.navbar-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  list-style: none;
}

.navbar-item {
  position: relative;
}

.navbar-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-dark);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast);
  border-bottom: 2px solid transparent;
}

.navbar-link:hover,
.navbar-link.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-accent);
}

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

.dropdown-toggle::after {
  content: '▼';
  font-size: 0.6em;
  margin-left: var(--spacing-xs);
  transition: transform var(--transition-fast);
}

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

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  background-color: var(--color-background);
  border: 1px solid rgba(15, 23, 42, 0.08);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  list-style: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-fast);
  margin-top: var(--spacing-sm);
}

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

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

.dropdown-item:hover {
  background-color: var(--color-background-light);
  color: var(--color-primary);
  border-left-color: var(--color-accent);
  padding-left: calc(var(--spacing-lg) + 4px);
}

.dropdown-divider {
  height: 1px;
  background-color: var(--color-border);
  margin: var(--spacing-sm) 0;
}

/* 汉堡菜单 */
.navbar-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

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

.navbar-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(10px, 10px);
}

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

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

/* ========== 页面主体 ========== */
main {
  margin-top: 70px;
  min-height: calc(100vh - 70px);
}

/* ========== 页脚 ========== */
.footer {
  background: linear-gradient(140deg, #012a4a 0%, #013c6b 50%, #04506f 100%);
  color: white;
  padding: var(--spacing-3xl) var(--container-padding);
  margin-top: var(--spacing-4xl);
}

.footer-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.footer-section h3 {
  color: white;
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-lg);
}

.footer-section ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-section li {
  margin-bottom: var(--spacing-sm);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-section a:hover {
  color: white;
  text-decoration: underline;
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
}

.contact-icon {
  font-size: var(--font-size-lg);
  flex-shrink: 0;
  margin-top: 2px;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.contact-label {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.6);
}

.contact-value {
  color: white;
  font-weight: var(--font-weight-medium);
}

.footer-divider {
  height: 1px;
  background-color: rgba(255, 255, 255, 0.1);
  margin: var(--spacing-2xl) 0;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-copyright {
  color: rgba(255, 255, 255, 0.6);
  font-size: var(--font-size-sm);
}

.footer-social {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
}

.social-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  color: white;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.social-link:hover {
  background-color: var(--color-primary);
  transform: translateY(-3px);
}

/* ========== 响应式设计 ========== */
@media (max-width: 768px) {
  .navbar-container {
    height: 60px;
    padding: var(--spacing-sm) var(--container-padding);
  }
  
  .navbar-toggle {
    display: flex;
  }
  
  .navbar-menu {
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
  }
  
  .navbar-menu.active {
    max-height: 500px;
  }
  
  .navbar-item {
    width: 100%;
  }
  
  .navbar-link {
    width: 100%;
    padding: var(--spacing-md) var(--container-padding);
    border-bottom: 1px solid var(--color-border);
    border-bottom-color: transparent;
  }
  
  .dropdown-menu {
    position: static;
    opacity: 0;
    visibility: hidden;
    max-height: 0;
    overflow: hidden;
    transform: none;
    border: none;
    box-shadow: none;
    background-color: var(--color-background-light);
    margin: 0;
    border-radius: 0;
    transition: all var(--transition-fast);
  }
  
  .dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    max-height: 500px;
  }
  
  .dropdown-item {
    padding: var(--spacing-sm) var(--spacing-lg) var(--spacing-sm) calc(var(--spacing-lg) + var(--spacing-lg));
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .footer-bottom {
    flex-direction: column;
  }
  
  main {
    margin-top: 60px;
    min-height: calc(100vh - 60px);
  }
}

@media (max-width: 480px) {
  .navbar-brand-text {
    display: none;
  }
  
  .navbar-menu {
    max-height: 0;
  }
  
  .navbar-menu.active {
    max-height: 400px;
  }
}