Even after adding the background-color property it is showing error
<!DOCTYPE html>
<html>
<head>
<title>CSS Selectors</title>
<style>
a:hover {
font-weight: bold;
text-decoration: none;
background-color: yellow;
}
</style>
</head>
<body>
<h1><a href="#">Studytonight</a><h1>
</body>
</html>