JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>Позиционирование слоёв</title>
  <style>
  body {
    font: 40pt Verdana, sans-serif;
    margin: 0;
  }
  div {
    border: 1px solid;
    position: absolute;
    top: 50%;
    left: 50%;
  }
  </style>
 </head>
 <body>
  <div>Самоучитель</div>
 </body>
</html>