ference
            {
                background-color: black;
                width: 1in;
                margin-top: 5px;
            }
            #test
            {
                border-right-style: solid;
                border-right-width: 2.54cm;
                width: 0;
            }
        </style>
    </head>
    <body>
        <p>Test passes if the 2 black squares have the <strong>same width</strong>.</p>
        <div id="test"></div>
        <div id="reference"></div>
    </body>
</html>