.site-header {
  position: relative;
  z-index: 1000;
  background-color: var(--bg-elevated);
  border-bottom: 1px solid var(--border-subtle);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: 64px;
  padding-block: var(--space-3);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
  text-decoration: none;
  color: var(--text-primary);
}

.site-header__logo {
  width: 40px;
  height: 40px;
  object-fit: contain;
  display: block;
}

.site-header__brand-text {
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-primary);
  line-height: 1;
}

.site-header__nav {
  display: flex;
  align-items: center;
  margin-left: auto;
}

.site-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-header__nav-list li {
  margin: 0;
  padding: 0;
}

.site-header__nav-link {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-caption-size);
  font-weight: var(--text-overline-weight);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-secondary);
  text-decoration: none;
  padding-block: var(--space-2);
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.site-header__nav-link:hover {
  color: var(--text-primary);
}

.site-header__nav-link[aria-current="page"] {
  color: var(--text-primary);
  border-bottom: 2px solid var(--accent-baize);
}

.site-header__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  width: 44px;
  height: 44px;
  padding: 0;
  background: none;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.site-header__toggle:hover {
  border-color: var(--border-strong);
}

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

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

@media (max-width: 767px) {
  .site-header__inner {
    min-height: 56px;
    padding-block: var(--space-2);
  }

  .site-header__logo {
    width: 32px;
    height: 32px;
  }

  .site-header__brand-text {
    font-size: 12px;
  }

  .site-header__toggle {
    display: flex;
  }

  .site-header__nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-elevated);
    border-bottom: 1px solid var(--border-subtle);
    box-shadow: var(--shadow-elevated);
    padding: var(--space-4);
    max-height: calc(100vh - 100%);
    overflow-y: auto;
    display: none;
  }

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

  .site-header__nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-2);
  }

  .site-header__nav-link {
    display: block;
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-sm);
  }

  .site-header__nav-link:hover {
    background-color: var(--bg-sunken);
  }

  .site-header__nav-link[aria-current="page"] {
    border-bottom: none;
    background-color: var(--bg-sunken);
    color: var(--text-primary);
  }
}