/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: var(--z-index-fixed);
  background-color: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-md);
  transition: background-color var(--transition-normal), box-shadow var(--transition-normal);
}

[data-theme="dark"] .header {
  background-color: rgba(17, 24, 39, 0.95);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 7rem;
  position: relative;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary-500);
}

.logo-icon {
  margin-right: var(--spacing-2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary-500);
}

/* Navigation */
.main-nav {
  position: absolute;
  top: 100%;
  left: 0;
  width: 100%;
  background-color: var(--color-bg-primary);
  box-shadow: var(--shadow-md);
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
  z-index: var(--z-index-dropdown);
  margin-top: 25px;
}

.main-nav.active {
  max-height: 50rem;
}

.nav-list {
  display: flex;
  flex-direction: column;
  padding: var(--spacing-3) 0;
}

.nav-item {
  position: relative;
}

.nav-item a {
  display: flex;
  align-items: center;
  padding: var(--spacing-3) var(--spacing-4);
  color: var(--color-text-primary);
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-item a:hover,
.nav-item.active a {
  color: var(--color-primary-500);
  background-color: var(--color-bg-secondary);
}

/* Dropdown */
.has-dropdown > a svg {
  margin-left: var(--spacing-1);
  transition: transform var(--transition-fast);
}

.has-dropdown.active > a svg {
  transform: rotate(180deg);
}

.dropdown {
  display: none;
  background-color: var(--color-bg-secondary);
  padding-left: var(--spacing-4);
}

.dropdown.active {
  display: block;
}

.dropdown a {
  padding: var(--spacing-2) var(--spacing-4);
  font-size: var(--font-size-sm);
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
}

.theme-toggle {
  margin-right: var(--spacing-3);
  color: var(--color-text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-1);
  border-radius: var(--border-radius-full);
  background-color: var(--color-bg-tertiary);
  transition: background-color var(--transition-fast);
  margin-left: 20px;
}

.theme-toggle:hover {
  background-color: var(--color-neutral-300);
}

.theme-toggle svg {
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.theme-toggle svg:first-child {
  opacity: 1;
  transform: scale(1);
}

.theme-toggle svg:last-child {
  position: absolute;
  opacity: 0;
  transform: scale(0.5);
}

[data-theme="dark"] .theme-toggle svg:first-child {
  opacity: 0;
  transform: scale(0.5);
}

[data-theme="dark"] .theme-toggle svg:last-child {
  opacity: 1;
  transform: scale(1);
}

/* Mobile Nav Toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 2.4rem;
  height: 2rem;
  cursor: pointer;
  z-index: 10;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 0.2rem;
  background-color: var(--color-text-primary);
  border-radius: var(--border-radius-full);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(0.9rem) rotate(45deg);
}

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

.nav-toggle.active span:nth-child(3) {
  transform: translateY(-0.9rem) rotate(-45deg);
}

/* Desktop Navigation */
@media (min-width: 1024px) {
  .nav-toggle {
    display: none;
  }
  
  .main-nav {
    position: static;
    max-height: none;
    overflow: visible;
    box-shadow: none;
    width: auto;
    background-color: transparent;
  }
  
  .nav-list {
    flex-direction: row;
    padding: 0;
  }
  
  .nav-item a {
    padding: var(--spacing-2) var(--spacing-3);
  }
  
  .nav-item a:hover,
  .nav-item.active a {
    background-color: transparent;
  }
  
  /* Desktop Dropdown */
  .dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 20rem;
    padding: var(--spacing-2) 0;
    background-color: var(--color-bg-primary);
    box-shadow: var(--shadow-lg);
    border-radius: var(--border-radius-md);
    z-index: var(--z-index-dropdown);
  }
  
  .has-dropdown:hover .dropdown {
    display: block;
  }
  
  .dropdown a {
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-base);
  }
  
  .has-dropdown > a:hover svg {
    transform: rotate(180deg);
  }
}