JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    width: 50px;
    height: 50px;
    border: 3px solid black;
    animation: ani1 3s 0s 3, ani2 3s 0s 2;
    //animation-iteration-count: infinite;
}
@keyframes ani1 {
    from { background: green; }
    50% { background: red; }
    to { background: green; }    
}
@keyframes ani2 {
    from { width: 100px; }
    50% { width: 150px; }
    to { width: 100px; }    
}