/* ============================================
   HEADER STYLES
   ============================================ */

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

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
  gap: var(--space-6);
}

.brand {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.brand__name {
  font-family: var(--font-serif);
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.brand:hover .brand__name {
  color: var(--color-primary-hover);
  text-decoration: none;
}

.main-nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-list a {
  display: block;
  padding: var(--space-2) 0;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  position: relative;
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition-base);
}

.nav-list a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.header-action {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2);
  color: var(--color-text);
  font-size: var(--text-base);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.header-action:hover {
  color: var(--color-primary);
  background-color: var(--color-background-secondary);
  text-decoration: none;
}

.action-label {
  font-size: var(--text-sm);
}

.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
}

/* Mobile Navigation */
@media (max-width: 768px) {
  .main-nav {
    position: fixed;
    top: 4.5rem;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-surface);
    padding: var(--space-6);
    transform: translateX(100%);
    transition: transform var(--transition-slow);
    justify-content: flex-start;
    overflow-y: auto;
  }
  
  .main-nav.is-open {
    transform: translateX(0);
  }
  
  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-4);
    width: 100%;
  }
  
  .nav-list li {
    width: 100%;
    border-bottom: 1px solid var(--color-border);
  }
  
  .nav-list a {
    padding: var(--space-4) 0;
    font-size: var(--text-lg);
  }
  
  .mobile-menu-toggle {
    display: flex;
  }
  
  .action-label {
    display: none;
  }
  
  .header-action i {
    font-size: var(--text-xl);
  }
}