/* 布局样式 - 导航栏和页脚 */

/* ========== 导航栏 ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--color-bg-primary);
  box-shadow: var(--box-shadow-base);
  z-index: var(--z-index-fixed);
  transition: all var(--transition-base) var(--transition-timing);
}

.header.scrolled {
  box-shadow: var(--box-shadow-md);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.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;
}

.logo-text {
  margin-left: var(--spacing-sm);
}

.nav {
  display: flex;
  align-items: center;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  list-style: none;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  text-decoration: none;
  transition: color var(--transition-base) var(--transition-timing);
}

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

/* 下拉菜单 */
.nav-item.has-dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  background-color: var(--color-bg-primary);
  box-shadow: var(--box-shadow-lg);
  border-radius: var(--border-radius-base);
  padding: var(--spacing-sm) 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-base) var(--transition-timing);
  z-index: var(--z-index-dropdown);
  list-style: none;
}

.dropdown-item {
  display: block;
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  text-decoration: none;
  transition: all var(--transition-base) var(--transition-timing);
}

.dropdown-item:hover {
  background-color: var(--color-bg-secondary);
  color: var(--color-primary);
}

/* 移动端菜单按钮 */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  color: var(--color-text-primary);
  cursor: pointer;
}

/* 页面内容区域 */
.main-content {
  margin-top: var(--header-height);
  min-height: calc(100vh - var(--header-height));
}

/* ========== 页脚 ========== */
.footer {
  background-color: var(--color-bg-dark);
  color: var(--color-text-white);
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.footer-section {
  display: flex;
  flex-direction: column;
}

.footer-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-text-white);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  list-style: none;
}

.footer-link {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color var(--transition-base) var(--transition-timing);
}

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

.footer-text {
  color: rgba(255, 255, 255, 0.8);
  line-height: var(--line-height-relaxed);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-lg);
  text-align: center;
}

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

/* ========== 响应式设计 ========== */
@media (max-width: 992px) {
  .nav-menu {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-bg-primary);
    flex-direction: column;
    align-items: stretch;
    padding: var(--spacing-lg);
    box-shadow: var(--box-shadow-lg);
    gap: 0;
  }

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

  .nav-item {
    border-bottom: 1px solid var(--color-border-light);
  }

  .nav-link {
    padding: var(--spacing-md) 0;
  }

  .dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    background-color: var(--color-bg-secondary);
    margin-top: var(--spacing-sm);
    display: none;
  }

  .nav-item.has-dropdown.active .dropdown-menu {
    display: block;
  }

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

  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .header-container {
    padding: 0 var(--spacing-md);
  }

  .logo {
    font-size: var(--font-size-lg);
  }

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