.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  width: 100%;
  border-bottom: 1px solid var(--border-dark);
  background: var(--color-night-950);
  color: var(--text-on-dark);
}

.site-header__inner {
  display: flex;
  width: min(100% - (var(--page-padding) * 2), var(--container-max));
  min-height: 5.25rem;
  margin-inline: auto;
  align-items: center;
  gap: var(--space-5);
}

.site-header__brand {
  display: inline-flex;
  min-width: 0;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-on-dark);
  text-decoration: none;
  white-space: nowrap;
}

.site-header__brand:hover { color: var(--text-on-dark); }

.site-header__mark {
  width: 2.5rem;
  height: 2.5rem;
  flex: 0 0 2.5rem;
  object-fit: contain;
}

.site-header__brand-name {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1;
}

.site-header__nav {
  display: flex;
  min-width: 0;
  flex: 1 1 auto;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-5);
}

.site-header__nav-list {
  display: flex;
  min-width: 0;
  margin: 0;
  padding: 0;
  align-items: center;
  gap: clamp(0.75rem, 1.35vw, 1.5rem);
  list-style: none;
}

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

.site-header__nav-list a {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  border-bottom: 1px solid transparent;
  color: var(--text-on-dark);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
}

.site-header__nav-list a:hover,
.site-header__nav-list a[aria-current="page"] {
  border-color: var(--color-copper-500);
  color: var(--color-copper-300);
}

.site-header__reserve,
.site-header__nav-reserve {
  flex: 0 0 auto;
  min-height: 3rem;
  white-space: nowrap;
}

.site-header__nav-reserve,
.site-header__toggle,
.site-header__nav-mobile-only { display: none; }

.site-header__toggle {
  width: 2.75rem;
  height: 2.75rem;
  flex: 0 0 2.75rem;
  padding: 0.75rem 0.625rem;
  background: transparent;
  color: var(--text-on-dark);
}

.site-header__toggle-line {
  display: block;
  width: 100%;
  height: 1px;
  margin-block: 0.28rem;
  background: currentColor;
  transform-origin: center;
  transition: transform var(--transition-control), opacity var(--transition-control);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(1) { transform: translateY(0.38rem) 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(-0.38rem) rotate(-45deg); }

@media (max-width: 72rem) {
  .site-header__inner { min-height: 4.75rem; gap: var(--space-3); }
  .site-header__nav-list { gap: var(--space-3); }
  .site-header__nav-list a { font-size: 0.75rem; }
}

@media (max-width: 62rem) {
  .site-header__inner { justify-content: space-between; }
  .site-header__mark { width: 2.125rem; height: 2.125rem; flex-basis: 2.125rem; }
  .site-header__brand-name { font-size: 1.25rem; }
  .site-header__toggle { display: block; margin-left: auto; }
  .site-header__reserve { display: inline-flex; min-height: 2.75rem; padding-inline: var(--space-4); }
  .site-header__nav {
    position: fixed;
    z-index: 101;
    top: 4.75rem;
    right: 0;
    bottom: 0;
    display: flex;
    width: min(25rem, 100%);
    padding: var(--space-6) var(--page-padding);
    overflow-y: auto;
    visibility: hidden;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    border-left: 1px solid var(--border-dark);
    background: var(--color-night-900);
    box-shadow: var(--shadow-float);
    opacity: 0;
    pointer-events: none;
    transform: translateX(100%);
    transition: transform var(--transition-control), opacity var(--transition-control), visibility var(--transition-control);
  }
  .site-header__nav.is-open { visibility: visible; opacity: 1; pointer-events: auto; transform: translateX(0); }
  .site-header__nav-list { width: 100%; flex-direction: column; align-items: stretch; gap: 0; }
  .site-header__nav-list a { min-height: 3.25rem; justify-content: space-between; border-bottom-color: var(--border-dark); font-size: var(--text-meta); }
  .site-header__nav-mobile-only { display: list-item; }
  .site-header__nav-reserve { display: inline-flex; width: 100%; margin-top: auto; }
}

@media (max-width: 29rem) {
  .site-header__inner { min-height: 4.5rem; }
  .site-header__brand { gap: var(--space-2); }
  .site-header__reserve { display: none; }
  .site-header__nav { top: 4.5rem; width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .site-header__nav { transition: none; }
}