JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  <div class="content"> 
    <h1>Header</h1>
    <p>Paragraph 1.</p>
    <p>Paragraph 2.</p>
    <p>Paragraph 3.</p>
  </div>
</body>

CSS

body {
  background-color: yellow;
  padding: 0px;
  margin: 0px;
}

h1 {
    margin:0;
  background-color: lime;
}

.content {
  background-color: pink;
  position: absolute;
  left: 0px;
  top: 0px;
  padding: 0px;
  margin: 0px;
}