JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Header</h1>

<h2>Header 2</h2>

<h3>Too Thin</h3>

CSS

h1
  { text-align: center;
    border: double black 3px;
    padding: 1em;
    margin: 1em;
}

h2
  { text-align: center;
    border-radius: 25px;
    border: double green 20px;
    padding: 1em;
    margin: 1em;
}

h3
  { text-align: center;
    border: double black 2px;
    padding: 1em;
    margin: 1em;
}