@keyframes xjump {
    
    0% {
      width: 75%;
      height: 75%;
    }
    100% {
      width: -75%;
      height: -75%;
    }
  }
.xjump {
    animation-name: xjump;
    animation-duration: 500ms;
    animation-fill-mode: forwards;
    color: red;
  }