/* ========================================
   导航栏和页面布局样式
   ======================================== */

/* ========== 固定导航栏 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: transparent;
  border-bottom: 1px solid transparent;
  box-shadow: none;
  z-index: var(--z-fixed);
  transition: background-color var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
}

.navbar.scrolled {
  background-color: var(--color-bg-white);
  border-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.navbar-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
  padding: 0 var(--spacing-4);
}

/* ========== Logo ========== */
.navbar-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  text-decoration: none;
  color: var(--color-text-primary);
  transition: color var(--transition-fast);
}

.navbar-logo:hover {
  color: var(--color-primary-dark);
}

.logo-mark {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.02em;
}

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

.logo-cn {
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  white-space: nowrap;
}

.logo-en {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  letter-spacing: 0.08em;
  white-space: nowrap;
}

/* ========== 导航菜单 ========== */
.navbar-menu {
  display: flex;
  align-items: center;
  flex-wrap: nowrap;
  gap: var(--spacing-1);
  list-style: none;
}

.navbar-item {
  position: relative;
}

.navbar-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-2);
  color: var(--color-white);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-sm);
  white-space: nowrap;
  transition: color var(--transition-fast);
  position: relative;
}

.navbar-link:hover {
  color: var(--color-white);
}

.navbar-link.active {
  color: var(--color-white);
}

.navbar-link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 12px;
  width: 0;
  height: 2px;
  background-color: var(--color-white);
  transition: width var(--transition-fast);
}

.navbar-link:hover::after,
.navbar-link.active::after {
  width: 100%;
}

.navbar.scrolled .navbar-link {
  color: var(--color-text-primary);
}

.navbar.scrolled .navbar-link:hover {
  color: var(--color-primary);
}

.navbar.scrolled .navbar-link::after,
.navbar.scrolled .navbar-link.active::after {
  background-color: var(--color-primary);
}

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

.navbar-dropdown > .navbar-link::after {
  content: none;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-none);
  box-shadow: var(--shadow-sm);
  min-width: 200px;
  display: none;
  z-index: var(--z-dropdown);
  list-style: none;
  margin-top: 0;
}

.navbar-dropdown:hover .dropdown-menu {
  display: block;
}
.navbar-dropdown:focus-within .dropdown-menu {
  display: block;
}

.dropdown-item {
  display: block;
  padding: var(--spacing-3) var(--spacing-4);
  color: var(--color-text-primary);
  text-decoration: none;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  border-left: 3px solid transparent;
  border-radius: 0;
}

.dropdown-item:hover {
  background-color: var(--color-bg-light);
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  padding-left: calc(var(--spacing-4) + 2px);
}

/* ========== 右侧操作栏 ========== */
.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
}

.navbar-btn {
  padding: var(--spacing-2) var(--spacing-4);
  font-size: var(--font-size-sm);
  border-radius: var(--radius-sm);
}

.navbar-actions .btn {
  border-radius: var(--radius-sm);
  padding: var(--spacing-2) var(--spacing-4);
}

.navbar:not(.scrolled) .navbar-actions .btn {
  background: transparent;
  color: var(--color-white);
  border: 1px solid rgba(255, 255, 255, 0.85);
}

.navbar:not(.scrolled) .navbar-actions .btn:hover {
  background: var(--color-white);
  color: var(--color-primary);
}

.navbar.scrolled .navbar-actions .btn {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border: 1px solid var(--color-primary);
}

/* ========== 移动菜单按钮 ========== */
.navbar-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-xl);
  color: var(--color-white);
}

.navbar.scrolled .navbar-toggle {
  color: var(--color-text-primary);
}

/* ========== 页面主体 ========== */
main {
  margin-top: 80px;
  min-height: calc(100vh - 80px);
}

/* ========== 页脚 ========== */
footer {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: var(--spacing-16) var(--spacing-4);
  margin-top: var(--spacing-20);
}

.footer-content {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--spacing-8);
  margin-bottom: var(--spacing-10);
}

.footer-section h3 {
  color: var(--color-white);
  margin-bottom: var(--spacing-4);
  font-size: var(--font-size-lg);
}

footer p {
  color: rgba(255, 255, 255, 0.85);
  line-height: var(--line-height-relaxed);
}

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

.footer-section li {
  margin-bottom: var(--spacing-2);
  color: rgba(255, 255, 255, 0.8);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-section a:hover {
  color: var(--color-white);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: var(--spacing-6);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-4);
}

.footer-copyright {
  color: var(--color-gray-400);
  font-size: var(--font-size-sm);
}

.footer-social {
  display: flex;
  gap: var(--spacing-3);
}

.footer-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-none);
  transition: all var(--transition-fast);
}

.footer-social a:hover {
  background-color: var(--color-white);
  color: var(--color-primary);
  border-color: var(--color-white);
}

/* ========== 响应式导航栏 ========== */
@media (max-width: 1024px) {
  .navbar-content {
    height: 60px;
  }

  .navbar-toggle {
    display: block;
  }

  .navbar-menu {
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background-color: var(--color-bg-white);
    flex-direction: column;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
  }

  .navbar-menu.active {
    max-height: 500px;
  }

  .navbar-item {
    width: 100%;
  }

  .navbar-link {
    width: 100%;
    padding: var(--spacing-4);
    border-radius: 0;
    color: var(--color-text-primary);
  }

  .dropdown-menu {
    position: static;
    max-height: 0;
    overflow: hidden;
    transform: none;
    border: none;
    box-shadow: none;
    background-color: var(--color-bg-light);
    margin: 0;
    transition: max-height var(--transition-base);
  }

  .navbar-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    max-height: 300px;
  }

  .dropdown-item {
    padding-left: var(--spacing-8);
  }

  .dropdown-item:hover {
    padding-left: calc(var(--spacing-8) + 2px);
  }
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-6);
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .navbar-logo {
    font-size: var(--font-size-base);
  }

  .navbar-logo img {
    height: 32px;
  }

  .navbar-actions {
    gap: var(--spacing-2);
  }

  .navbar-btn {
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-xs);
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .footer-section {
    border-bottom: 1px solid var(--color-gray-700);
    padding-bottom: var(--spacing-4);
  }

  .footer-section:last-child {
    border-bottom: none;
  }
}