.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-base);
  border-bottom: 1px solid var(--border-subtle);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad-mobile);
  height: 64px;
}

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

.site-header__brand:hover {
  text-decoration: none;
}

.site-header__logo {
  width: 40px;
  height: 40px;
  object-fit: contain;
  flex-shrink: 0;
}

.site-header__brand-text {
  font-family: var(--font-heading);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-primary);
  white-space: nowrap;
}

.site-header__toggle {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  min-height: 44px;
  min-width: 44px;
  padding: 8px;
  border-radius: var(--radius-sm);
  background: none;
  border: none;
  cursor: pointer;
  flex-shrink: 0;
}

.site-header__toggle-line {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 1px;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(2) {
  opacity: 0;
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.site-header__toggle:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 2px;
}

.site-header__nav {
  display: none;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  background-color: var(--bg-base);
  border-bottom: 1px solid var(--border-subtle);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
  padding: var(--space-md);
  max-height: calc(100vh - 64px);
  overflow-y: auto;
  z-index: 999;
}

.site-header__nav.is-open {
  display: block;
}

.site-header__nav-list {
  list-style: none !important;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.site-header__nav-item {
  margin: 0;
  padding: 0;
}

.site-header__nav-link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  min-height: 44px;
  line-height: 1.2;
}

.site-header__nav-link:hover {
  color: var(--text-primary);
  background-color: var(--bg-elevated);
  text-decoration: none;
}

.site-header__nav-link[aria-current="page"] {
  color: var(--accent-cyan);
  background-color: rgba(0, 229, 199, 0.1);
}

.site-header__cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  min-height: 44px;
  min-width: 44px;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  background-color: var(--accent-cyan);
  color: var(--bg-base);
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-decoration: none;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
  margin-top: var(--space-sm);
}

.site-header__cta:hover {
  background-color: #00c4ab;
  text-decoration: none;
}

.site-header__cta:active {
  transform: scale(0.98);
}

.site-header__cta:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 2px;
}

@media (min-width: 768px) {
  .site-header__inner {
    padding-inline: var(--container-pad-tablet);
  }
}

@media (min-width: 1024px) {
  .site-header__inner {
    padding-inline: var(--container-pad-desktop);
    height: 72px;
  }

  .site-header__logo {
    width: 44px;
    height: 44px;
  }

  .site-header__brand-text {
    font-size: 22px;
  }

  .site-header__toggle {
    display: none;
  }

  .site-header__nav {
    display: flex;
    position: static;
    top: auto;
    left: auto;
    right: auto;
    background: none;
    border: none;
    box-shadow: none;
    padding: 0;
    max-height: none;
    overflow: visible;
    align-items: center;
    gap: var(--space-lg);
    flex: 1;
    justify-content: flex-end;
  }

  .site-header__nav-list {
    flex-direction: row;
    gap: var(--space-md);
    align-items: center;
  }

  .site-header__nav-link {
    display: inline-flex;
    align-items: center;
    padding: var(--space-xs) var(--space-sm);
    font-size: 14px;
    min-height: 44px;
    line-height: 1.2;
    border-radius: var(--radius-sm);
    white-space: nowrap;
  }

  .site-header__nav-link[aria-current="page"] {
    color: var(--accent-cyan);
    background: none;
    box-shadow: inset 0 -2px 0 0 var(--accent-cyan);
  }

  .site-header__cta {
    margin-top: 0;
    flex-shrink: 0;
  }
}