JSFiddle - React, Tailwind, and code Playground

HTML

<div id="target"></div>

CSS

@-webkit-keyframes anim {
    0% {
        width: 10%;
    }
    100% {
        width: 50%;
    }
}
#target {
    -webkit-animation: anim 0.5s 1 ease-in-out;
    height: 200px;
    width: 50%;
    background: red;
}