JSFiddle - React, Tailwind, and code Playground

HTML

<table class="tab">
   <tr>
    <td>asdf</td><td>afda</td><td>asdfdsa</td>
   </tr>

   <tr>
    <td colspan="3">
      <table>
       <tr>
          <td>afds</td><td>Trkaladf</td><td>inner Tab</td>
       </tr>
      </table>
    </td>
   </tr>

  </table>

CSS

table.tab tr{
     background:red;
   }