#scrollTopBtn {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 48px;
  height: 48px;
  border: none;
  border-radius: 50%;
  background: #111827;
  color: white;
  font-size: 20px;
  cursor: pointer;
  display: none;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
  transition:
    opacity 0.2s ease,
    transform 0.2s ease;
  z-index: 1000;
}

#scrollTopBtn:hover {
  transform: translateY(-2px);
  background: #1f2937;
}