examples/fundamentals__chrome-remote-debugging/index.html

<html>

<head>
    <style>
        #printable {
            display: none;
        }

        #pseudo-hover span {
            display: none;
        }

        #pseudo-hover:hover span {
            display: block;
        }

        @media print {
            #printable {
                display: block;
            }

            #not-in-printable {
                display: none;
            }
        }
    </style>
</head>

<body>
    <div id="not-in-printable">not visible if print media query is activated</div>
    <div id="printable">
        <h1>This is displayed only in "print" mode</h1>
    </div>
    <div id="pseudo-hover">
        <h1>Hover over this element</h1>
        <span>Display only on hover</span>
    </div>
</body>

</html>