JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <thead>
        <tr>
            <th><span>This is a really long header</span></th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>foo</td>
        </tr>
    </tbody>
</table>

CSS

table, td { border: solid 1px black }

th
{
    background-color: red;
    max-width: 50px;
}

span
{
    overflow: hidden;
    display: block;
    width: 50px;
    white-space: nowrap;
    text-overflow: ellipsis;
}