Get your own website Result Size: 625 x 565
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<!DOCTYPE html>
<html>
<head>
<style>
#div1 {
  position: relative;
  box-sizing: border-box;
  margin: auto;
  height: 150px;
  width: 200px;
  padding: 10px;
  border: 1px solid black;
}
#div2 {
  padding: 40px;
  box-sizing: border-box;
  position: absolute;
  border: 1px solid black;
  background-color: red;
  aspect-ratio: 5/2; 
}
</style>
</head>
<body>
<h1>The aspect-ratio Property</h1>
<div id="div1">DIV1
  <div id="div2">DIV2</div>
</div>
</body>
</html>