@import "tailwindcss";

@theme {
}

@keyframes asd {
    0% {
        opacity: 1;
    }
    10%,
    100% {
        opacity: 0;
    }
    50%,
    100% {
        width: 0;
        margin: 0;
    }
  }

#main {
  width: 450px;
  height: 200px;
  border: solid 1px black;
  margin: 100px;
  display: flex;
  justify-content: center;
}

#one {
  width: 200px;
  height: 200px;
  border: solid 1px red;
}

#second {
  position: static;
  visibility: visible;
  width: 200px;
  height: 200px;
  border: solid 1px blue;
}

#main:hover {
  animation-duration: 1s;
  animation-name: make-small;
  animation-fill-mode: forwards;
}

#main > *{
  margin: 0 auto;
  }

#main:hover #second {
  animation-duration: 1s;
  animation-name: asd;
  animation-fill-mode: forwards;
}

done: https://play.tailwindcss.com/JniN5UninR?file=css