.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  border-bottom: 1px solid var(--color-line);
  background: var(--color-canvas);
  color: var(--color-ink);
}

.site-header__inner {
  display: grid;
  grid-template-columns: minmax(0, auto) minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(1rem, 2vw, 2rem);
  width: min(100% - (var(--container-padding) * 2), var(--container-max));
  min-height: 5.25rem;
  margin-inline: auto;
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  min-width: 0;
  gap: 0.7rem;
  color: var(--color-ink);
  text-decoration: none;
}

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

.site-header__mark {
  flex: 0 0 2.625rem;
  width: 2.625rem;
  height: 2.625rem;
  object-fit: contain;
}

.site-header__brand-name {
  white-space: nowrap;
  font-family: var(--font-heading);
  font-size: clamp(1.3rem, 1.8vw, 1.65rem);
  line-height: 1;
  letter-spacing: -0.035em;
}

.site-header__nav {
  min-width: 0;
}

.site-header__nav-list,
.site-header__mobile-links {
  display: flex;
  align-items: center;
  gap: clamp(0.7rem, 1.45vw, 1.45rem);
  margin: 0;
  padding: 0;
  list-style: none;
}

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

.site-header__nav-list a,
.site-header__mobile-links a {
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  color: var(--color-ink);
  font-size: 0.73rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.01em;
  text-decoration: none;
  text-decoration-color: var(--color-burgundy);
  text-underline-offset: 0.35em;
  white-space: nowrap;
}

.site-header__nav-list a:hover,
.site-header__mobile-links a:hover {
  color: var(--color-cobalt);
  text-decoration: underline;
  text-decoration-thickness: 2px;
}

.site-header__mobile-links { display: none; }

.site-header__action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--color-cobalt);
  border-radius: var(--radius-control);
  background: var(--color-cobalt);
  color: var(--color-paper);
  font-size: 0.72rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.01em;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
}

.site-header__action:hover { background: var(--color-cobalt-deep); color: var(--color-paper); }

.site-header__toggle { display: none; }

.site-header :focus-visible { outline: none; box-shadow: var(--focus-light); }

@media (max-width: 1099px) {
  .site-header__inner {
    grid-template-columns: minmax(0, 1fr) auto auto;
    min-height: 4.75rem;
  }

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

  .site-header__toggle {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.28rem;
    width: 2.75rem;
    min-width: 2.75rem;
    height: 2.75rem;
    padding: 0;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-control);
    background: transparent;
    color: var(--color-ink);
  }

  .site-header__toggle:hover { background: var(--color-paper); }

  .site-header__toggle-line {
    display: block;
    width: 1.15rem;
    height: 1px;
    background: currentColor;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
  }

  .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); }

  .site-header__nav {
    position: fixed;
    top: 4.75rem;
    right: 0;
    left: 0;
    z-index: 99;
    display: grid;
    align-content: start;
    gap: 1.5rem;
    max-height: calc(100dvh - 4.75rem);
    padding: 1.5rem var(--container-padding) 2rem;
    overflow-y: auto;
    border-top: 1px solid var(--color-line);
    border-bottom: 1px solid var(--color-line);
    background: var(--color-paper);
    box-shadow: var(--shadow-panel);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-0.5rem);
    transition: opacity var(--transition-base), transform var(--transition-base);
  }

  .site-header__nav.is-open { opacity: 1; pointer-events: auto; transform: translateY(0); }

  .site-header__nav-list,
  .site-header__mobile-links {
    display: grid;
    gap: 0;
  }

  .site-header__mobile-links { display: grid; padding-top: 1rem; border-top: 1px solid var(--color-line); }

  .site-header__nav-list a,
  .site-header__mobile-links a {
    min-height: 3rem;
    border-bottom: 1px solid var(--color-line);
    font-size: 0.9rem;
  }
}

@media (max-width: 599px) {
  .site-header__inner { gap: 0.65rem; }
  .site-header__brand { gap: 0.5rem; }
  .site-header__brand-name { font-size: 1.25rem; }
  .site-header__action { min-height: 2.75rem; padding-inline: 0.65rem; font-size: 0.66rem; }
}