JSFiddle - React, Tailwind, and code Playground

HTML

<div id="infowindow">á</div>

CSS

#infowindow {
    border: 1px solid blue;
    width: 300px;
    height: 200px;    
}

#infowindow:after {
    display: block;
    position: absolute;
    top: 10%;
    left: 25%;
}