/* Header Layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-gray-100);
  box-shadow: var(--shadow-sm);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
  gap: var(--space-4);
}

/* Brand */
.brand {
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.brand:hover {
  color: var(--color-primary);
}

/* Mobile Navigation */
.primary-nav {
  display: none;
  position: fixed;
  inset: 0;
  top: 4.5rem;
  background-color: var(--color-surface);
  padding: var(--space-6);
  overflow-y: auto;
  z-index: 98;
}

.primary-nav.is-open {
  display: block;
}

.nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin: 0;
  padding: 0;
}

.nav-link {
  display: block;
  padding: var(--space-3) 0;
  font-size: var(--text-lg);
  font-weight: 500;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-gray-100);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-primary);
  padding-left: var(--space-2);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 101;
}

.hamburger {
  position: relative;
  width: 1.5rem;
  height: 2px;
  background-color: var(--color-text);
  transition: background-color var(--transition-fast);
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-text);
  transition: transform var(--transition-base), top var(--transition-base);
}

.hamburger::before {
  top: -6px;
}

.hamburger::after {
  top: 6px;
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger {
  background-color: transparent;
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-full);
  color: var(--color-text);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.icon-btn:hover {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

/* Mobile Overlay */
.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  top: 4.5rem;
  background-color: rgba(74, 66, 61, 0.5);
  backdrop-filter: blur(4px);
  z-index: 97;
}

.mobile-overlay.is-visible {
  display: block;
}

/* Desktop Styles */
@media (min-width: 768px) {
  .mobile-menu-toggle {
    display: none;
  }
  
  .primary-nav {
    display: block;
    position: static;
    padding: 0;
    background: transparent;
    overflow: visible;
  }
  
  .nav-list {
    flex-direction: row;
    align-items: center;
    gap: var(--space-8);
  }
  
  .nav-link {
    font-size: var(--text-base);
    font-weight: 400;
    border-bottom: none;
    padding: var(--space-2) 0;
    position: relative;
  }
  
  .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-primary);
    transition: width var(--transition-base);
  }
  
  .nav-link:hover {
    padding-left: 0;
    color: var(--color-primary);
  }
  
  .nav-link:hover::after {
    width: 100%;
  }
  
  .mobile-overlay {
    display: none !important;
  }
}