JSFiddle - React, Tailwind, and code Playground

HTML

<div class="zentriert">Zentriert :-)</div>

CSS

html {
   height: 100%;
 }

 body {
   font: 50% sans-serif;
   background-color: #dddddd;
   height: 100%;
   display: -webkit-box;
   display: -webkit-flex;
   display: -ms-flexbox;
   display: flex;
   -webkit-box-align: center;
   -webkit-align-items: center;
   -ms-flex-align: center;
   align-items: center;
   -webkit-box-pack: center;
   -webkit-justify-content: center;
   -ms-flex-pack: v;
   justify-content: left;
 }

 .zentriert {
   background-color: #227a7d;
   color: rgba(182, 236, 230, 0.93);
   padding: 1em;
   border: 1px solid #236b6e;
   border-radius: 4px;
 }