.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  min-height: 4.75rem;
  border-bottom: 1px solid var(--color-steel-line);
  background: var(--color-charcoal-950);
  color: var(--color-off-white);
}

.site-header__inner {
  display: flex;
  min-height: 4.75rem;
  align-items: center;
  gap: var(--space-4);
}

.site-header__brand {
  display: inline-flex;
  min-width: 0;
  flex: 0 1 auto;
  align-items: center;
  gap: 0.625rem;
  color: var(--color-off-white);
  text-decoration: none;
}

.site-header__brand:hover {
  color: var(--color-soft-copper);
}

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

.site-header__brand-text {
  min-width: 0;
  font-family: var(--font-heading);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  line-height: 1;
  text-transform: uppercase;
  white-space: nowrap;
}

.site-header__desktop-nav {
  min-width: 0;
  margin-left: auto;
}

.site-header__desktop-nav nav,
.site-header__desktop-nav ul {
  margin: 0;
  padding: 0;
}

.site-header__desktop-nav ul {
  display: flex;
  align-items: center;
  gap: clamp(0.5rem, 1.3vw, 1.25rem);
  list-style: none;
}

.site-header__desktop-nav li,
.site-header__desktop-nav li+li {
  margin: 0;
  padding: 0;
}

.site-header__desktop-nav a {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  border-bottom: 3px solid transparent;
  color: var(--color-off-white);
  font-family: var(--font-heading);
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: 0.035em;
  line-height: 1;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.site-header__desktop-nav a:hover,
.site-header__desktop-nav a[aria-current="page"] {
  border-bottom-color: var(--color-rust);
  color: var(--color-off-white);
}

.site-header__actions {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: var(--space-3);
}

.site-header__book {
  min-height: 2.75rem;
  padding-inline: 0.875rem;
}

.site-header__toggle {
  display: none;
  width: 2.75rem;
  min-height: 2.75rem;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  padding: 0.5rem;
  border: 1px solid var(--color-steel-line);
  border-radius: var(--radius-control);
  background: transparent;
  color: var(--color-off-white);
}

.site-header__toggle span {
  display: block;
  width: 1.25rem;
  height: 1px;
  background: currentColor;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.site-header__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}

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

.site-header__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

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

.site-header__mobile-nav {
  position: absolute;
  z-index: 1;
  top: 100%;
  right: 0;
  left: 0;
  max-height: calc(100vh - 4.75rem);
  overflow-y: auto;
  border-bottom: 1px solid var(--color-steel-line);
  background: var(--color-charcoal-950);
  box-shadow: var(--shadow-floating);
}

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

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

.site-header__mobile-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.site-header__mobile-group p {
  margin: 0;
  color: var(--color-soft-copper);
  font-size: var(--text-label);
  font-weight: 600;
  letter-spacing: 0.12em;
  line-height: var(--line-label);
  text-transform: uppercase;
}

.site-header__mobile-group ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--color-dark-divider);
}

.site-header__mobile-group li,
.site-header__mobile-group li+li {
  margin: 0;
  padding: 0;
  border-bottom: 1px solid var(--color-dark-divider);
}

.site-header__mobile-group a {
  display: flex;
  min-height: 2.75rem;
  align-items: center;
  color: var(--color-off-white);
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
}

.site-header__mobile-group a:hover {
  color: var(--color-soft-copper);
}

@media (max-width: 71.9375rem) {
  .site-header__desktop-nav {
    display: none;
  }

  .site-header__inner {
    justify-content: space-between;
  }

  .site-header__actions {
    margin-left: auto;
  }

  .site-header__toggle {
    display: flex;
    flex-direction: column;
  }
}

@media (max-width: 29.9375rem) {
  .site-header {
    min-height: 4.25rem;
  }

  .site-header__inner {
    min-height: 4.25rem;
    gap: var(--space-2);
  }

  .site-header__mark {
    width: 2.125rem;
    height: 2.125rem;
  }

  .site-header__brand {
    gap: 0.5rem;
  }

  .site-header__brand-text {
    font-size: 0.6875rem;
    letter-spacing: 0.08em;
  }

  .site-header__book {
    padding-inline: 0.625rem;
  }

  .site-header__mobile-nav {
    max-height: calc(100vh - 4.25rem);
  }

  .site-header__mobile-group ul {
    grid-template-columns: 1fr;
  }
}

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