JSFiddle - React, Tailwind, and code Playground

HTML

<table>
 <tr>
   <td class="a b">1</td><td class="a">2</td><td class="a b">3</td>
 </tr>
 <tr>
   <td class="a">4</td><td class="a b">5</td><td class="b">6</td>
 </tr>
</table>

CSS

.b{
background-color:grey;
}
.a{
background-color:red;
}
.a.b{
background-color:green;
}