<!DOCTYPE html>
<html lang="en">
<head>
<title>Learn CSS</title>
</head>
<body>
<div class="grid">
<div class="column">
100px
</div>
<div class="column">
50px
</div>
<div class="column">
20%
</div>
<div class="column">
50px
</div>
</div>
</body>
</html>