.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  width: 100%;
  height: 4rem;
  border-bottom: 1px solid var(--color-line);
  background: rgb(243 245 247 / 0.92);
  backdrop-filter: blur(12px);
}

.site-header__inner {
  display: grid;
  width: min(100% - (var(--container-padding) * 2), var(--container-max));
  height: 100%;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--space-4);
  margin-inline: auto;
}

.site-header__desktop-nav,
.site-header__desktop-actions,
.site-header__nav-list,
.site-header__brand,
.site-header__age-mark,
.site-header__toggle {
  min-width: 0;
}

.site-header__nav-list,
.site-header__mobile-list {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 1.5vw, 1.5rem);
  margin: 0;
  padding: 0;
  list-style: none;
}

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

.site-header__desktop-nav--left {
  justify-self: start;
}

.site-header__desktop-actions {
  display: flex;
  align-items: center;
  justify-self: end;
  gap: var(--space-4);
}

.site-header__link,
.site-header__mobile-link {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  border-bottom: 1px solid transparent;
  color: var(--color-ink-soft);
  font-size: 1rem;
  font-weight: 500;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.site-header__link:hover,
.site-header__link[aria-current="page"] {
  border-bottom-color: var(--color-accent);
  color: var(--color-ink);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  justify-self: center;
  gap: 0.625rem;
  color: var(--color-ink);
  text-decoration: none;
  white-space: nowrap;
}

.site-header__logo {
  width: 2.5rem;
  height: 2.5rem;
  flex: 0 0 2.5rem;
  padding: 0;
  object-fit: contain;
  border-radius: 0.35rem;
}

.site-header__brand-text {
  font-family: var(--font-heading);
  font-size: 1.0625rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1;
}

.site-header__age-mark {
  display: inline-flex;
  min-height: 1.5rem;
  align-items: center;
  padding-inline: 0.5rem;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-ink);
  font-size: var(--text-label);
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1;
  text-decoration: none;
}

.site-header__age-mark:hover {
  border-color: var(--color-accent);
  color: var(--color-accent-deep);
}

.site-header__toggle {
  display: none;
  position: relative;
  width: 2.75rem;
  height: 2.75rem;
  align-items: center;
  justify-content: center;
  justify-self: end;
  padding: 0;
  border: 1px solid var(--color-line);
  background: var(--color-panel);
  color: var(--color-ink);
}

.site-header__toggle:hover {
  border-color: var(--color-accent);
  background: var(--color-panel-soft);
}

.site-header__toggle-line {
  position: absolute;
  width: 1.25rem;
  height: 1px;
  background: currentColor;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

.site-header__toggle-line:nth-child(1) { transform: translateY(-0.375rem); }
.site-header__toggle-line:nth-child(3) { transform: translateY(0.375rem); }

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

.site-header__mobile-nav {
  position: fixed;
  z-index: 99;
  inset: 4rem 0 0;
  overflow-y: auto;
  border-top: 1px solid var(--color-line);
  background: var(--color-paper);
}

.site-header__mobile-nav[hidden] {
  display: none !important;
}

.site-header__mobile-nav-inner {
  display: flex;
  width: min(100% - (var(--container-padding) * 2), var(--container-max));
  min-height: 100%;
  flex-direction: column;
  gap: var(--space-6);
  margin-inline: auto;
  padding-block: var(--space-6) var(--space-8);
}

.site-header__mobile-nav-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-line);
}

.site-header__mobile-nav-label {
  color: var(--color-ink-soft);
  font-size: var(--text-label);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.site-header__mobile-list {
  flex-direction: column;
  align-items: stretch;
  gap: 0;
}

.site-header__mobile-list li {
  border-bottom: 1px solid var(--color-line);
}

.site-header__mobile-link {
  width: 100%;
  min-height: 3.5rem;
  justify-content: space-between;
  border: 0;
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 8vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.site-header__mobile-link::after {
  content: "→";
  color: var(--color-ink-muted);
  font-family: var(--font-body);
  font-size: 1rem;
}

.site-header__mobile-link:hover,
.site-header__mobile-link[aria-current="page"] {
  color: var(--color-accent);
}

.site-header__mobile-link--accent::after {
  color: var(--color-accent);
}

@media (max-width: 64rem) {
  .site-header {
    height: 3.5rem;
  }

  .site-header__inner {
    grid-template-columns: 1fr auto 1fr;
  }

  .site-header__desktop-nav,
  .site-header__desktop-actions {
    display: none;
  }

  .site-header__toggle {
    display: inline-flex;
  }

  .site-header__logo {
    width: 1.75rem;
    height: 1.75rem;
    flex-basis: 1.75rem;
  }

  .site-header__brand-text {
    font-size: 0.9375rem;
  }

  .site-header__mobile-nav {
    inset-top: 3.5rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header__toggle-line,
  .site-header__link,
  .site-header__mobile-link {
    transition: none;
  }
}