.collapse {
  display: block;
}
.collapse.in {
  display: none;
}
.collapse.am-collapse {
  animation-duration: 0.3s;
  animation-timing-function: ease;
  animation-fill-mode: backwards;
  overflow: hidden;
}
.collapse.am-collapse.in-remove {
  animation-name: collapse;
  display: block;
}
.collapse.am-collapse.in-add {
  animation-name: expand;
}