details[open] summary ~ * {
    animation: sweep .5s ease-in-out;
  }
  
  @keyframes sweep {
    0%    {opacity: 0; margin-left: -20px}
    100%  {opacity: 1; margin-left: 0px}
  }


summary {
    display: list-item !important;
}

details[open] ::-webkit-details-marker
{
    transform: rotate(90deg);
}