<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Color 4: CSS Color 4: prophoto-rgb</title>
<style>
    body { background-color: grey; }
    .test { background-color: lab(100% 0.0131 0.0085); width: 12em; height: 12em; } /* color(prophoto-rgb 1 1 1) converted to Lab */
</style>
<body>
    <p>Test passes if you see a single square, and not two rectangles of different colors.</p>
    <div class="test"></div>
</body>