How to set initial property state on CSS Animation?

I need to create a animation with the fallowing steps:

1. Initial: elementA with opacity 0;
2. Once hover elementA's container (let's call it containerA):
   • elementA translate from (-5px, 5px) to (0px, 0px);
     
   • elementA change opacity from 0 to 1;
   • animation duration: 0.5s;
3. Once mouse leave containerA:
   • elementA change opacity from 1 to 0;
   • elementA doesn't change translate position;
   • animation duration: 0.5s;

I've achieved this effect by adding/removing CSS class, you can see the here (https://jsbin.com/buqexadiru/edit?html,css,js,console,output)

My question is, how can I achieve this effect with pure CSS, without the add/remove class step; Is this possible?

Use a transition for the opacity and an animation for the transform when the container is hovered.

.container {
  margin: 1em;
  border: 2px solid blue;
  background: lightblue;
  width: 50vh;
  aspect-ratio: 1;
}

.item {
  width: 20vh;
  aspect-ratio: 1;
  background: green;
  opacity: 0;
  transform: translate(0%, 0%);
  transition: opacity .5s;
}

.container:hover .item {
  opacity: 1;
  animation-name: appear;
  animation-duration: .5s;
  animation-fill-mode: forwards;
}

@keyframes appear {
  0% {
    transform: translate(-50%, -50%);
  }
  100% {
    transform: translate(0%, 0%);
  }
}

<div class="container">
  <div class="item"></div>
</div>