/* Header Layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-neutral-200);
  height: var(--header-height);
}

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

/* Logo */
.logo {
  font-family: var(--font-serif);
  font-size: var(--text-2xl);
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: -0.02em;
  z-index: 101;
}

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

/* Primary Navigation */
.primary-navigation {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  gap: var(--space-8);
  list-style: none;
}

.nav-list a {
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
  padding: var(--space-2) 0;
  position: relative;
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background-color: var(--color-primary);
  transition: width var(--transition-base);
}

.nav-list a:hover {
  color: var(--color-primary);
}

.nav-list a:hover::after {
  width: 100%;
}

/* Utilities */
.header-utilities {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.icon-button {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.icon-button:hover {
  color: var(--color-primary);
  background-color: var(--color-neutral-100);
}

/* Mobile Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 0;
  z-index: 101;
}

.hamburger {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: transform var(--transition-base), opacity var(--transition-fast);
  transform-origin: center;
}

/* Responsive */
@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: flex;
    order: 3;
  }
  
  .primary-navigation {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-surface);
    padding: var(--space-8) var(--space-6);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    flex-direction: column;
    justify-content: flex-start;
    align-items: flex-start;
  }
  
  .primary-navigation.is-open {
    transform: translateX(0);
  }
  
  .nav-list {
    flex-direction: column;
    gap: var(--space-6);
    width: 100%;
  }
  
  .nav-list a {
    font-size: var(--text-2xl);
    text-transform: none;
    letter-spacing: normal;
    font-family: var(--font-serif);
  }
  
  .nav-list a::after {
    display: none;
  }
  
  /* Hamburger Animation */
  .mobile-menu-toggle[aria-expanded="true"] .hamburger:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger:nth-child(2) {
    opacity: 0;
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
}