<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
input:focus {
background-color: #ccc;
}
</style>
</head>
<body>
<h2>:focus selector example</h2>
<form>
Name:
<input type="text" name="name"> Surname:
<input type="text" name="surname">
</form>
</body>
</html>