<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>
<header id="header">
  <p>Basic Responsive Design</p>
</header>
<div id="content">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut ac nibh sapien. Ut faucibus eget orci non gravida.</p>
</div>
</body>
</html>
html {
  height: 100%;
}
body {
  height: inherit;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}

#content {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
  justify-content: center;
  align-items: center;
}
#header {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100px;
  background-color: #eee;
}
#header p {
  font-size: 1.1em;
  text-transform: uppercase;
}

#content p {
  font-size: 1em;
  text-align: center;
  max-width: 90%;
  margin: 0 auto;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.