.sina-demo-banner {
  position: sticky;
  top: 0;
  background: #0f3d68;
  color: #fff;
  text-align: center;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.35rem 0.75rem;
  z-index: 2000;
}

[data-bs-theme="dark"] .sina-demo-banner {
  background: #1a4f82;
  color: #f4f7fb;
}