/* Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in oklab, var(--color-bg) 90%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-divider);
  transition: box-shadow var(--transition-interactive);
}

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

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-4);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  flex-shrink: 0;
}

.nav-logo-mark {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.nav-logo-img {
  height: clamp(46px, 5.5vw, 58px);
  width: auto;
  display: block;
  flex-shrink: 0;
}

@media (max-width: 768px) {
  .nav-logo-img { height: 42px; }
}

.nav-logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.nav-logo-name {
  font-family: var(--font-display);
  font-size: clamp(1rem, 0.9rem + 0.5vw, 1.25rem);
  font-weight: 500;
  color: var(--color-text);
  letter-spacing: 0.02em;
}

.nav-logo-tagline {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-8);
  list-style: none;
}

.nav-links a {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--color-text-muted);
  text-decoration: none;
  position: relative;
  padding-bottom: 2px;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-primary);
  transition: width var(--transition-interactive);
}

.nav-links a:hover { color: var(--color-text); }
.nav-links a:hover::after { width: 100%; }
.nav-links a.active { color: var(--color-primary); }
.nav-links a.active::after { width: 100%; }

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  background: transparent;
  border: 1px solid var(--color-border);
}
.theme-toggle:hover { color: var(--color-text); border-color: var(--color-primary); }

/* Mobile nav */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: var(--space-1);
  background: none;
  border: none;
  cursor: pointer;
}
.nav-hamburger span {
  display: block;
  height: 1.5px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all 0.3s ease;
}

.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--color-bg);
  z-index: 200;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
}

.mobile-nav.open { display: flex; }
.mobile-nav a {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 400;
  color: var(--color-text);
  text-decoration: none;
}
.mobile-nav a:hover { color: var(--color-primary); }

.mobile-nav-close {
  position: absolute;
  top: var(--space-6);
  right: var(--space-6);
  font-size: 2rem;
  color: var(--color-text-muted);
  background: none;
  border: none;
  cursor: pointer;
  line-height: 1;
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
  .nav-logo-tagline { display: none; }
}