.site-header {
  position: relative;
  z-index: 100;
  min-height: 5.25rem;
  border-bottom: var(--border-dark);
  background: var(--colour-midnight-950);
  color: var(--colour-paper-50);
}

.site-header__inner {
  display: flex;
  min-height: 5.25rem;
  align-items: center;
  gap: var(--space-4);
}

.site-header__brand {
  display: inline-flex;
  min-width: 0;
  flex: 0 1 auto;
  align-items: center;
  gap: var(--space-3);
  color: var(--colour-white);
  text-decoration: none;
}

.site-header__brand:hover { color: var(--colour-arcade-yellow-400); }
.site-header__logo { width: 2.5rem; height: 2.5rem; flex: 0 0 2.5rem; object-fit: contain; }
.site-header__brand-copy { display: grid; min-width: 0; gap: 0.125rem; }
.site-header__brand-name { font-family: var(--font-heading); font-size: 1.125rem; font-weight: 700; letter-spacing: -0.03em; line-height: 1; white-space: nowrap; }
.site-header__descriptor { color: var(--colour-paper-200); font-family: var(--font-heading); font-size: 0.5625rem; font-weight: 700; letter-spacing: 0.08em; line-height: 1.2; text-transform: uppercase; white-space: nowrap; }

.site-header__navigation { min-width: 0; flex: 1 1 auto; }
.site-header__navigation-inner { display: flex; min-width: 0; align-items: center; gap: var(--space-3); }
.site-header__primary-list { display: flex; min-width: 0; align-items: center; gap: var(--space-3); margin: 0; padding: 0; list-style: none; }
.site-header__primary-list li,
.site-header__primary-list li + li { margin: 0; padding: 0; }
.site-header__primary-list a { display: inline-flex; min-height: 2.75rem; align-items: center; color: var(--colour-paper-50); font-family: var(--font-heading); font-size: 0.75rem; font-weight: 700; letter-spacing: 0.045em; line-height: 1.2; text-decoration: none; text-transform: uppercase; white-space: nowrap; }
.site-header__primary-list a:hover,
.site-header__primary-list a:focus-visible { color: var(--colour-arcade-yellow-400); text-decoration: underline; }
.site-header__route-rail { display: none; }
.site-header__route-title { color: var(--colour-paper-200); font-family: var(--font-heading); font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; }
.site-header__play { min-height: 2.75rem; flex: 0 0 auto; padding-inline: 0.75rem; font-size: 0.6875rem; white-space: nowrap; }
.site-header__toggle,
.site-header__mobile-only { display: none; }

@media (max-width: 1080px) {
  .site-header__inner { gap: var(--space-3); }
  .site-header__descriptor { display: none; }
  .site-header__primary-list { gap: var(--space-2); }
  .site-header__primary-list a { font-size: 0.6875rem; }
}

@media (max-width: 900px) {
  .site-header { min-height: 4.5rem; }
  .site-header__inner { min-height: 4.5rem; }
  .site-header__toggle { display: inline-flex; width: 2.75rem; height: 2.75rem; flex: 0 0 2.75rem; align-items: center; justify-content: center; border: var(--border-dark); border-radius: var(--radius-control); background: var(--colour-midnight-900); color: var(--colour-paper-50); }
  .site-header__toggle:hover { border-color: var(--colour-cyan-400); color: var(--colour-cyan-400); }
  .site-header__toggle-lines { display: grid; width: 1.125rem; gap: 0.25rem; }
  .site-header__toggle-lines span { display: block; height: 2px; background: currentColor; transition: transform var(--transition-fast), opacity var(--transition-fast); }
  .site-header__toggle[aria-expanded="true"] .site-header__toggle-lines span:nth-child(1) { transform: translateY(0.375rem) rotate(45deg); }
  .site-header__toggle[aria-expanded="true"] .site-header__toggle-lines span:nth-child(2) { opacity: 0; }
  .site-header__toggle[aria-expanded="true"] .site-header__toggle-lines span:nth-child(3) { transform: translateY(-0.375rem) rotate(-45deg); }
  .site-header__navigation { position: absolute; top: 100%; left: 0; width: 100%; max-height: calc(100vh - 4.5rem); overflow: auto; visibility: hidden; border-bottom: var(--border-dark); background: var(--colour-midnight-900); box-shadow: var(--shadow-floating); opacity: 0; transform: translateY(-0.5rem); transition: opacity var(--transition-fast), transform var(--transition-fast), visibility var(--transition-fast); }
  .site-header__navigation.is-open { visibility: visible; opacity: 1; transform: translateY(0); }
  .site-header__navigation-inner { display: grid; gap: var(--space-4); padding: var(--space-4) max(var(--gutter), calc((100% - var(--container-width)) / 2)); }
  .site-header__primary-list { display: grid; gap: 0; }
  .site-header__primary-list a { width: 100%; min-height: 2.75rem; border-bottom: var(--border-dark); font-size: 0.875rem; }
  .site-header__mobile-only { display: list-item; }
  .site-header__primary-list .route-marker { margin-inline-end: var(--space-2); font-size: 0.5625rem; }
  .site-header__route-rail { display: flex; align-items: center; gap: var(--space-2); overflow-x: auto; padding-block: var(--space-2); white-space: nowrap; }
}

@media (max-width: 540px) {
  .site-header__inner { gap: var(--space-2); }
  .site-header__brand { gap: var(--space-2); }
  .site-header__logo { width: 2.125rem; height: 2.125rem; flex-basis: 2.125rem; }
  .site-header__brand-name { font-size: 1rem; }
  .site-header__play { min-width: 0; padding-inline: 0.5rem; font-size: 0.5625rem; letter-spacing: 0.04em; }
}

@media (prefers-reduced-motion: reduce) { .site-header__navigation, .site-header__toggle-lines span { transition: none; } }