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

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 5rem;
}

/* Brand Identity */
.brand {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: var(--color-text);
  transition: opacity var(--transition-fast);
}

.brand:hover {
  opacity: 0.8;
}

.brand__name {
  font-size: var(--text-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-asphalt);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.brand__tagline {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: var(--font-weight-medium);
}

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

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

.nav-list a {
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.025em;
  padding: var(--space-2) 0;
  position: relative;
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  z-index: 101;
}

.hamburger {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-asphalt);
  position: relative;
  transition: background-color var(--transition-fast);
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
  width: 24px;
  height: 2px;
  background-color: var(--color-asphalt);
  transition: transform var(--transition-base);
}

.hamburger::before {
  top: -7px;
}

.hamburger::after {
  top: 7px;
}

/* Mobile Responsive Styles */
@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: block;
  }
  
  .primary-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-surface);
    box-shadow: var(--shadow-lg);
    padding: var(--space-6) var(--container-padding);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
  }
  
  .primary-nav.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-list {
    flex-direction: column;
    gap: var(--space-4);
    width: 100%;
  }
  
  .nav-list a {
    display: block;
    padding: var(--space-3) 0;
    font-size: var(--text-lg);
  }
  
  /* Hamburger Animation when open */
  .mobile-menu-toggle[aria-expanded="true"] .hamburger {
    background-color: transparent;
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger::before {
    transform: translateY(7px) rotate(45deg);
  }
  
  .mobile-menu-toggle[aria-expanded="true"] .hamburger::after {
    transform: translateY(-7px) rotate(-45deg);
  }
}

/* Enhanced Focus States */
.brand:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}