#back-to-top {
  display: none;
  position: fixed;
  bottom: 30px;
  right: 30px;
  padding: 12px 12px;
  background-color: #0080ff;
  color: #ffffff;
  border: none;
  border-radius: 6px;
  font-weight: bold;
  font-size: 16px;
  cursor: pointer;
  z-index: 9999;
  transition: opacity 0.3s ease, background-color 0.3s ease, color 0.3s ease;
  text-decoration: none;
}
#back-to-top:hover {
  background-color: #555555 !important;
  color: #ffffff !important;
}