.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 100;
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

.site-header.scrolled {
  background: rgba(10, 10, 10, 0.95);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.5);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
}

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

.nav-logo img {
  height: 48px;
  width: auto;
}

.nav-logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.nav-brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-text-primary);
}

.nav-tagline {
  font-size: var(--text-xs);
  color: var(--color-accent);
}

/* Nav Links */
.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.nav-link {
  padding: 0.5rem 1rem;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--border-radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text-primary);
}

.nav-link.active {
  color: var(--color-accent);
  background-color: var(--color-accent-subtle);
}

/* Mobile Toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
  z-index: 110;
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.hamburger {
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

/* Hamburger open state */
.nav-toggle[aria-expanded="true"] .hamburger {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

/* Mobile nav */
@media (max-width: 767px) {
  .nav-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 0;
    right: 0;
    width: min(300px, 80vw);
    height: 100vh;
    flex-direction: column;
    justify-content: center;
    gap: var(--space-md);
    background: rgba(10, 10, 10, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transform: translateX(100%);
    transition: transform var(--transition-slow);
    padding: var(--space-xl);
  }

  .nav-menu.open {
    transform: translateX(0);
  }

  .nav-link {
    font-size: var(--text-lg);
    padding: var(--space-sm) var(--space-md);
    width: 100%;
    text-align: center;
  }

  .nav-logo-text {
    display: none;
  }
}