css/css-variables/reference/css-vars-custom-property-case-sensitive-ref.html

<!DOCTYPE html>
<html>
<head>
    <title>CSS Variables Test: custom property names are case-sensitive</title>
    <meta charset="UTF-8">
    <link rel="author" title="Noah Collins" href="mailto:noahcollins@gmail.com">
    <style type="text/css">
        .blue-good-1  { color: #22e; }
        .blue-good-2  { color: #22e; }
    </style>
</head>
<body>
    <h2 class="blue-good-1">Valid CSS Variable Names</h2>
    <p class="blue-good-1">This paragraph is styled using a valid CSS Variable name. It should be blue.</p>
    <p class="blue-good-2">This paragraph is styled using a valid CSS Variable name. It should be blue.</p>
    <br>
    <h2>Invalid CSS Variable Names</h2>
    <p>This paragraph is styled using an invalid CSS Variable name. Fail if red.</p>
    <p>This paragraph is styled using an invalid CSS Variable name. Fail if red.</p>
</body>
</html>