.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  transition: box-shadow var(--transition-normal), background-color var(--transition-normal);
}

.site-header.is-scrolled {
  box-shadow: var(--shadow-sm);
  background-color: #FFFFFF;
}

.header-container {
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

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

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 8px 4px;
  position: relative;
}

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

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

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.menu-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 10px;
  flex-direction: column;
  justify-content: space-around;
  border-radius: var(--border-radius-sm);
  border: 1px solid var(--border-color);
}

.menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-main);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}
.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

.scroll-progress-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  pointer-events: none;
}

.scroll-progress-fill {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary-dark), var(--color-primary-hover));
  transition: width 0.05s linear;
}

/* Menu Mobile Overlay */
.nav-mobile-overlay {
  position: fixed;
  inset: var(--header-height) 0 0 0;
  background-color: rgba(23, 25, 31, 0.4);
  backdrop-filter: blur(4px);
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}

.nav-mobile-overlay.is-active {
  opacity: 1;
  pointer-events: auto;
}

.nav-mobile-panel {
  position: fixed;
  top: var(--header-height);
  right: 0;
  width: 82%;
  max-width: 340px;
  bottom: 0;
  background: #FFFFFF;
  z-index: 1001;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-lg);
  overflow-y: auto;
}

.nav-mobile-panel.is-active {
  transform: translateX(0);
}

.nav-mobile-links {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.nav-mobile-link {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-main);
  padding: 12px 0;
  border-bottom: 1px solid var(--border-color);
}

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