/* ── Site Header ── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  gap: var(--space-lg);
}

@media (min-width: 768px) {
  .site-header__inner { padding: 0 var(--space-2xl); }
}

@media (min-width: 1400px) {
  .site-header__inner { padding: 0 var(--space-3xl); }
}

/* ── Logo ── */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}

.site-logo:hover { opacity: 0.85; text-decoration: none; }

.site-logo__img {
  width: 36px;
  height: 36px;
}

.site-logo__text {
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-navy);
  line-height: 1.2;
  max-width: 160px;
  display: none;
}

@media (min-width: 480px) {
  .site-logo__text { display: block; }
}

/* ── Nav ── */
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav__item { margin: 0; }

.site-nav__link {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-muted);
  text-decoration: none;
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}

.site-nav__link:hover {
  color: var(--color-ocean);
  background: var(--color-code-bg);
  text-decoration: none;
}

.site-nav__link[aria-current="page"],
.site-nav__link.is-active {
  color: var(--color-ocean);
  background: var(--color-code-bg);
  font-weight: 600;
}

.site-nav__icon {
  font-size: 1.1em;
  line-height: 1;
}

.site-nav__label { display: none; }

@media (min-width: 640px) {
  .site-nav__label { display: inline; }
}

/* ── Mobile hamburger ── */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.nav-toggle:hover { background: var(--color-code-bg); }

.nav-toggle__bar {
  width: 100%;
  height: 2px;
  background: var(--color-navy);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ── Mobile menu overlay ── */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(26,41,71,0.6);
  z-index: 99;
}

.mobile-nav.is-open { display: block; }

.mobile-nav__panel {
  background: var(--color-surface);
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
}

.mobile-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.mobile-nav__link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.mobile-nav__link:hover,
.mobile-nav__link[aria-current="page"] {
  background: var(--color-code-bg);
  color: var(--color-ocean);
  text-decoration: none;
}

@media (min-width: 768px) {
  .nav-toggle { display: none; }
}