<!DOCTYPE html>
<html>
<body>
<h1 style="background-color:hsl(0, 0%, 20%);">hsl(0, 0%, 20%)</h1>
<h1 style="background-color:hsl(0, 0%, 30%);">hsl(0, 0%, 30%)</h1>
<h1 style="background-color:hsl(0, 0%, 40%);">hsl(0, 0%, 40%)</h1>
<h1 style="background-color:hsl(0, 0%, 60%);">hsl(0, 0%, 60%)</h1>
<h1 style="background-color:hsl(0, 0%, 70%);">hsl(0, 0%, 70%)</h1>
<h1 style="background-color:hsl(0, 0%, 90%);">hsl(0, 0%, 90%)</h1>
</body>
</html>