details{overflow:hidden}details[open]>div{animation:slideDown .3s ease-in-out}details>div{animation:slideUp .3s ease-in-out}@keyframes slideDown{from{max-height:0;opacity:0}to{max-height:500px;opacity:1}}@keyframes slideUp{from{max-height:500px;opacity:1}to{max-height:0;opacity:0}}