JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <table>
        <tbody>
            <tr>
                <th>a</th>
                <th>b</th>
            </tr>
            <tr>
                <td>a</td>
                <td>b</td>
            </tr>
            <tr>
                <td>a</td>
                <td>b</td>
            </tr>
        </tbody>
    </table>
</body>

CSS

table
{
    border-collapse: separate;
}

tr
{
    border: 1px solid red;
}