/* ============================================
   SITE HEADER
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-gray-200);
  transition: box-shadow var(--transition-base);
}

.site-header--scrolled {
  box-shadow: var(--shadow-md);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
  gap: var(--space-6);
}

/* Brand/Logo */
.site-brand {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.site-name {
  font-family: var(--font-serif);
  font-size: var(--text-2xl);
  font-weight: 500;
  color: var(--color-text);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  transition: color var(--transition-fast);
}

.site-brand:hover .site-name {
  color: var(--color-primary);
}

/* Navigation */
.main-nav {
  display: flex;
  align-items: center;
  flex: 1;
  justify-content: center;
}

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

.nav-link {
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text);
  padding: var(--space-2) 0;
  position: relative;
  transition: color var(--transition-fast);
}

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

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

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

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

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  color: var(--color-text);
  transition: all var(--transition-fast);
  position: relative;
}

.icon-btn:hover {
  color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.icon-btn i {
  font-size: var(--text-lg);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  gap: 6px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 1.5px;
  background-color: var(--color-text);
  transition: all var(--transition-base);
  transform-origin: center;
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.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: translateY(-7.5px) rotate(-45deg);
}

/* Mobile Responsive */
@media (max-width: 1023px) {
  .mobile-menu-toggle {
    display: flex;
  }

  /* On mobile, brand is centred — push it with auto margins */
  .site-brand {
    flex: 1;
    justify-content: center;
  }

  .main-nav {
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-bg);
    justify-content: flex-start;
    align-items: flex-start;
    padding: var(--space-8) var(--container-padding);
    transform: translateX(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    overflow-y: auto;
  }
  
  .main-nav.is-open {
    transform: translateX(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-6);
    width: 100%;
  }
  
  .nav-item {
    width: 100%;
    border-bottom: 1px solid var(--color-gray-200);
    padding-bottom: var(--space-4);
  }
  
  .nav-link {
    font-size: var(--text-xl);
    font-family: var(--font-serif);
    text-transform: none;
    letter-spacing: 0.02em;
    display: block;
    width: 100%;
  }
  
  .nav-link::after {
    display: none;
  }
}

@media (max-width: 639px) {
  .header-container {
    height: 64px;
  }
  
  .site-name {
    font-size: var(--text-xl);
  }
  
  .main-nav {
    top: 64px;
  }
}