@keyframes dropdown {
  0%{
      display: block;
      opacity: 1;
      top: 100%;
      visibility: visible;
      
  }
  100%{
      display: none;
      opacity: 0;
      visibility: hidden;
      top: 90%;
  }
}
@keyframes dropdown_hover {
  0%{
      display: none;
      opacity: 0;
      visibility: hidden;
      top: 90%;
  }
  100%{
      display: block;
      opacity: 1;
      top: 100%;
      visibility: visible;
  }
}