/* Header Layout */
.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;
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}

/* Brand Identity */
.brand {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: 0.05em;
}

.brand-name {
  color: var(--color-sage-dark);
}

.brand-suffix {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 400;
}

/* Primary Navigation */
.primary-navigation {
  display: flex;

}

.nav-list {
  display: flex;
  gap: var(--space-8);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list a {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  padding: var(--space-2) 0;
  position: relative;
  transition: color var(--transition-fast);
}

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

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

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

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

.btn--small {
  padding: var(--space-2) var(--space-5);
  font-size: var(--text-sm);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 2.5rem;
  height: 2.5rem;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  z-index: 101;
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: all var(--transition-base);
  border-radius: var(--radius-full);
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: flex;
  }
  
  .primary-navigation {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    max-width: 320px;
    background-color: var(--color-surface);
    padding: calc(4.5rem + var(--space-8)) var(--space-6) var(--space-6);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    box-shadow: var(--shadow-xl);
    border-left: 1px solid var(--color-border);
  }
  
  .primary-navigation.is-open {
    transform: translateX(0);
  }
  
  .nav-list {
    flex-direction: column;
    gap: var(--space-2);
  }
  
  .nav-list li {
    border-bottom: 1px solid var(--color-border);
  }
  
  .nav-list a {
    font-size: var(--text-lg);
    padding: var(--space-4) 0;
    display: block;
  }
  
  .nav-list a::after {
    display: none;
  }
  
  .header-actions {
    display: none;
  }
  
  /* Hamburger Animation */
  .mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
    opacity: 0;
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }
}

/* Accessibility */
.mobile-menu-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-md);
}

body.menu-open {
  overflow: hidden;
}