.btn {
  cursor: pointer;
  opacity: 0.9;
  -webkit-filter: drop-shadow(1px 1px 2px rgba(0, 0, 0, 0.33));
  filter: drop-shadow(1px 1px 2px rgba(0, 0, 0, 0.33));
  -webkit-user-select: none;
  user-select: none;
}
.btn:hover {
  opacity: 1;
}