.site-header {
  background: rgba(6, 21, 47, 0.78);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.12);
}

.site-header.scrolled {
  background: rgba(6, 21, 47, 0.97);
  border-bottom-color: rgba(56, 189, 248, 0.3);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}