<html>
<head>
    <style>
        table { background-color: lightblue; height: 100px; }
        td { width: 100px; height: 50px; }
        div#target { height: 25px; width: 50px; background-color: lightgreen; }
    </style>
</head>
<body>
<table>
    <tr>
        <td>
            <div id="target"></div>
        </td>
    </tr>
</table>
</body>
</html>