<!DOCTYPE html>
<html lang="en-US">
<head>
<style media="screen and monochrome">
#mono{
color:green;
}
#no-mono{
color:#fff;
}
</style>
<style media="screen and (monochrome: 0)">
#no-mono{
color:green;
}
#mono{
color:#fff;
}
</style>
</head>
<body>
<p id="mono">You are using monochrome device.</p>
<p id="no-mono">You are not using monochrome device.</p>
</body>
</html>