JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td class="a" rowspan="2"><div>A</div></td>
        <td class="b"><div>B</div></td>
    </tr>
    <tr>
        <td class="c"><div>C</div></td>
    </tr>
</table>

CSS

td
{
    vertical-align: top;
}
td.a div
{
    background-color: #f00;
    height: 100%;
}