.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-asphalt);
  border-bottom: var(--border-default);
  box-shadow: none;
  transition: box-shadow var(--transition-fast);
}

.site-header.is-scrolled {
  box-shadow: var(--shadow-deep);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad-mobile);
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-chalk);
  flex-shrink: 0;
}

.brand-mark {
  width: 48px;
  height: 48px;
  object-fit: contain;
  display: block;
}

.brand-text {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  line-height: 1.2;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-chalk);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  width: 48px;
  height: 48px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--color-steel);
  border-radius: var(--radius-default);
  cursor: pointer;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.nav-toggle:hover {
  border-color: var(--color-ember);
}

.nav-toggle:focus-visible {
  outline: var(--border-focus);
  outline-offset: var(--focus-offset);
}

.nav-toggle-line {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-chalk);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  flex-shrink: 0;
}

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

.nav-list li {
  margin: 0;
  padding: 0;
}

.nav-list li + li {
  margin: 0;
}

.nav-list a {
  display: inline-block;
  padding: var(--space-xs) 0;
  font-family: var(--font-heading);
  font-size: 1rem;
  line-height: 1.2;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-chalk);
  text-decoration: none;
  position: relative;
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.nav-list a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-ember);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-fast);
}

.nav-list a:hover,
.nav-list a:focus-visible {
  color: var(--color-ember);
}

.nav-list a:hover::after,
.nav-list a:focus-visible::after {
  transform: scaleX(1);
}

.nav-list a:focus-visible {
  outline: var(--border-focus);
  outline-offset: var(--focus-offset);
}

.header-cta {
  flex-shrink: 0;
}

@media (max-width: 1023px) {
  .header-inner {
    min-height: 56px;
  }

  .brand-mark {
    width: 36px;
    height: 36px;
  }

  .brand-text {
    font-size: 1rem;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-asphalt);
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-lg);
    padding: var(--space-lg);
    overflow-y: auto;
    transform: translateX(100%);
    visibility: hidden;
    transition: transform var(--transition-fast), visibility var(--transition-fast);
    z-index: 999;
  }

  .site-nav.is-open {
    transform: translateX(0);
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-sm);
  }

  .nav-list a {
    display: block;
    padding: var(--space-sm) 0;
    font-size: 1.25rem;
  }

  .header-cta {
    width: 100%;
    justify-content: center;
  }
}

@media (min-width: 1024px) {
  .header-inner {
    min-height: 72px;
  }

  .brand-mark {
    width: 48px;
    height: 48px;
  }

  .brand-text {
    font-size: 1.25rem;
  }

  .nav-toggle {
    display: none;
  }

  .site-nav {
    position: static;
    transform: none;
    visibility: visible;
    overflow: visible;
    background: transparent;
    padding: 0;
    flex-direction: row;
    align-items: center;
    gap: var(--space-lg);
  }

  .nav-list {
    flex-direction: row;
    gap: var(--space-md);
  }

  .nav-list a {
    padding: var(--space-xs) 0;
    font-size: 1rem;
  }
}