JSFiddle - React, Tailwind, and code Playground

HTML

<table cellspacing="0" cellpadding="0" width="100%">
    <tr class="four-px">
        <td>ff</td>
        <td>ff</td>
        <td>ff</td>
    </tr>
    <tr>
        <td colspan="3">content</td>
    </tr>
    <tr class="four-px">
        <td>ff</td>
        <td>ff</td>
        <td>ff</td>
    </tr>
</table>

CSS

table, tr, td { background:#dd0;}
tr.four-px { height:4px;  }
tr.four-px td { background:#ff9; font-size:4px; line-height:1; }