JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container"> 
    <div id="vertical"> 
        Hello world! 
    </div>               
</div>

CSS

#vertical{ 
    position:absolute; 
    top:50%;     
    left:0; 
    width:100%; 
    text-align:center;
} 
#container {
    position:relative;
    height:200px;
    border:1px solid #000;
}