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

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

/* Logo */
.site-logo {
  text-decoration: none;
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.logo-text {
  font-family: var(--font-serif);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-graphite);
  letter-spacing: -0.02em;
}

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

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

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

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

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

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

/* CTA Button */
.header-cta {
  display: none;
}

@media (min-width: 768px) {
  .header-cta {
    display: inline-flex;
  }
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--color-concrete-light);
  color: var(--color-graphite);
  font-size: var(--text-lg);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all var(--duration-fast) var(--ease-out);
}

.mobile-menu-toggle:hover {
  background-color: var(--gray-100);
  border-color: var(--color-concrete);
}

.mobile-menu-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

@media (min-width: 768px) {
  .mobile-menu-toggle {
    display: none;
  }
}

/* Mobile Navigation Styles */
@media (max-width: 767px) {
  .nav-list {
    position: absolute;
    top: 80px;
    left: 0;
    right: 0;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-concrete-light);
    flex-direction: column;
    padding: var(--space-2) var(--space-4);
    gap: 0;
    box-shadow: var(--shadow-lg);
    
    /* Hidden by default */
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--duration-normal) var(--ease-out);
  }
  
  .nav-list.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  
  .nav-list li {
    width: 100%;
    border-bottom: 1px solid var(--gray-100);
  }
  
  .nav-list li:last-child {
    border-bottom: none;
  }
  
  .nav-list a {
    display: block;
    padding: var(--space-4) var(--space-2);
    font-size: var(--text-lg);
  }
  
  .nav-list a::after {
    display: none;
  }
}