JSFiddle - React, Tailwind, and code Playground

HTML

<div>

</div>

CSS

@keyframes taille {
    0% {width: 50px; background-color: red}
    75% {width: 200px; background-color: blue}
}

div {
    height: 100px;
    width: 200px;
    background-color: blue;
    animation-name: taille;
    animation-duration: 4s;
    animation-iteration-count: infinite;
    animation-direction: alternate;
}