.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
}
.site-header.scrolled { box-shadow: var(--shadow-md); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-navy);
  text-decoration: none;
  flex-shrink: 0;
}
.logo-icon {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, var(--color-trust-blue), var(--color-navy));
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-white);
  font-size: 1.2rem;
  flex-shrink: 0;
}
.logo-text span { color: var(--color-trust-blue); }

/* Desktop nav */
.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.nav-menu > a {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-mid);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}
.nav-menu > a:hover  { color: var(--color-navy); background: var(--color-silver-pale); }
.nav-menu > a.active { color: var(--color-trust-blue); }

/* Mobile-only elements hidden on desktop */
.nav-menu .nav-mobile-cta { display: none; }

/* Desktop CTA buttons */
.header-cta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}
.header-cta .btn-signin,
.header-cta .btn-join { display: flex; }

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  cursor: pointer;
  background: none;
  border: none;
  flex-shrink: 0;
}
.hamburger span {
  display: block;
  width: 24px; height: 2px;
  background: var(--color-navy);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== MOBILE ===== */
@media (max-width: 1024px) {
  /* Hide desktop nav */
  .nav-menu { display: none; }

  /* Hide desktop CTA buttons from header bar */
  .header-cta .btn-signin,
  .header-cta .btn-join  { display: none; }

  /* Show hamburger */
  .hamburger { display: flex; }

  /* Open mobile nav panel */
  .nav-menu.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 72px; left: 0; right: 0; bottom: 0;
    background: var(--color-white);
    padding: var(--space-4) var(--space-6) var(--space-8);
    gap: var(--space-1);
    box-shadow: var(--shadow-lg);
    z-index: var(--z-sticky);
    overflow-y: auto;
    border-top: 1px solid var(--color-border);
  }

  .nav-menu.open > a {
    font-size: var(--font-size-md);
    font-weight: 600;
    color: var(--color-text-dark);
    padding: var(--space-4) var(--space-3);
    border-radius: var(--radius-md);
    border-bottom: 1px solid var(--color-border);
    transition: background var(--transition-fast);
  }
  .nav-menu.open > a:last-of-type { border-bottom: none; }
  .nav-menu.open > a:hover { background: var(--color-silver-pale); }
  .nav-menu.open > a.active { color: var(--color-trust-blue); }

  /* Show mobile CTA buttons inside nav */
  .nav-menu .nav-mobile-cta {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    padding-top: var(--space-6);
    margin-top: var(--space-4);
    border-top: 2px solid var(--color-border);
  }
  .nav-mobile-cta .btn { text-align: center; min-height: 52px; }
}

@media (max-width: 400px) {
  .logo-text { font-size: var(--font-size-lg); }
}