JSFiddle - React, Tailwind, and code Playground

HTML

<fieldset>
    <legend>Header</legend>
    <div class="my-overflow">
        <table>
            <tr>
                <td>Val 1</td>
            </tr>
            <tr>
                <td>Val 2</td>
            </tr>
            <tr>
                <td>Val 3</td>
            </tr>
            <tr>
                <td>Val 4</td>
            </tr>
            <tr>
                <td>Val 5</td>
            </tr>
            <tr>
                <td>Val 6</td>
            </tr>
        </table>
    </div>
</fieldset>

CSS

fieldset {
        border: 1px solid lightgrey;
        padding: 20px;
        border-radius: 8px;
        background: #f9f9f9;
        padding: 5px;
        vertical-align: top;
        font-size: 11px;
    }
    .my-overflow {
        overflow-y: auto;
        height: 50px;
        max-height: 50px;
    }