JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box">Hi</div>

CSS

@-webkit-keyframes MOVE {
    0%   { opacity: 0; }
    100% { opacity: 1; }
}
@-moz-keyframes MOVE {
    0%   { opacity: 0; }
    100% { opacity: 1; }
}
@-ms-keyframes MOVE {
    0%   { opacity: 0; }
    100% { opacity: 1; }
}

#box {
     -webkit-animation: MOVE 5s infinite;
     -moz-animation:    MOVE 5s infinite;
     -ms-animation:     MOVE 5s infinite;
}