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<!DOCTYPE html>
<html>
<head>
<style>
#example1 {
  border: 2px solid black;
  padding: 25px;
  background: url(mountain.jpg);
  background-repeat: no-repeat;
  background-size: 100% 100%;
}
#example2 {
  border: 2px solid black;
  padding: 25px;
  background: url(mountain.jpg);
  background-repeat: no-repeat;
  background-size: 75% 50%;
}
</style>
</head>
<body>
<h2>background-size: 100% 100%:</h2>
<div id="example1">
  <h2>Hello World</h2>
  <p>The size of the background image is set in percent of the parent element; 100% width and 100% height.</p>
</div>
<h2>background-size: 75% 50%:</h2>
<div id="example2">
  <h2>Hello World</h2>
  <p>The size of the background image is set in percent of the parent element; 75% width and 50% height.</p>
</div>
</body>
</html>