JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td>
            <span id="A">A</span>
            <hr/>
            <span>B</span>
        </td>
        <td>1</td>
        <td>1</td>
        <td>1</td>
        <td>1</td>
    </tr>
</table>

CSS

td {
    width: 50px;
    border:1px solid black;
    text-align:center;
}


hr {
     -moz-transform: rotate(45deg);  
       -o-transform: rotate(45deg);  
  -webkit-transform: rotate(45deg);  
      -ms-transform: rotate(45deg);  
          transform: rotate(45deg);  
             width:150%;
    margin-left:-15px;
}