.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-base);
  border-bottom: 1px solid var(--border-steel);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: 64px;
  padding-block: var(--space-2);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--text-primary);
  flex-shrink: 0;
  min-width: 0;
}

.site-header__logo {
  width: 48px;
  height: 48px;
  object-fit: contain;
  flex-shrink: 0;
}

.site-header__brand-text {
  font-family: var(--font-heading);
  font-size: 1.125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: 1px solid var(--border-steel);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  flex-shrink: 0;
}

.nav-toggle:hover {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.2);
}

.nav-toggle:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 2px;
  box-shadow: var(--focus-glow);
}

.nav-toggle__line {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast), background-color var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
  background-color: var(--accent-amber);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
  background-color: var(--accent-amber);
}

.site-nav {
  display: flex;
  align-items: center;
  flex-shrink: 1;
  min-width: 0;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin: 0;
  padding: 0;
  list-style: none !important;
}

.site-nav__item {
  margin: 0;
  padding: 0;
  flex-shrink: 0;
}

.site-nav__item + .site-nav__item {
  margin: 0;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: var(--space-1) var(--space-2);
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--transition-fast), text-shadow var(--transition-fast);
  position: relative;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: var(--space-2);
  right: var(--space-2);
  bottom: 6px;
  height: 2px;
  background-color: var(--accent-cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-fast);
}

.site-nav__link:hover {
  color: var(--accent-cyan);
  text-shadow: 0 0 8px rgba(0, 229, 255, 0.5);
}

.site-nav__link:hover::after {
  transform: scaleX(1);
}

.site-nav__link:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 2px;
  box-shadow: var(--focus-glow);
}

@media (max-width: 1024px) {
  .site-header__inner {
    min-height: 56px;
    padding-block: var(--space-1);
  }

  .site-header__logo {
    width: 40px;
    height: 40px;
  }

  .site-header__brand-text {
    font-size: 1rem;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-base);
    border-bottom: 1px solid var(--border-steel);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.5);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-fast) ease-in-out;
    z-index: 999;
  }

  .site-nav.is-open {
    max-height: 400px;
    overflow-y: auto;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-2) var(--gutter);
  }

  .site-nav__item {
    width: 100%;
  }

  .site-nav__link {
    display: flex;
    width: 100%;
    min-height: 48px;
    padding: var(--space-2) var(--space-3);
    border-bottom: 1px solid var(--border-steel);
  }

  .site-nav__item:last-child .site-nav__link {
    border-bottom: none;
  }

  .site-nav__link::after {
    display: none;
  }
}

@media (max-width: 480px) {
  .site-header__inner {
    min-height: 48px;
    padding-block: var(--space-1);
  }

  .site-header__logo {
    width: 36px;
    height: 36px;
  }

  .site-header__brand-text {
    font-size: 0.875rem;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
    padding: 8px;
  }

  .nav-toggle__line {
    width: 20px;
  }
}