JSFiddle - React, Tailwind, and code Playground

HTML

Just some text
<div id="container">
    <table>
        <tr>
            <td class="first"></td>
            <td class="second"></td>
        </tr>
        <tr>
            <td class="first"></td>
            <td class="second"></td>
        </tr>
        <tr>
            <td class="first"><div class="indicator"></div></td>
            <td class="second"></td>
        </tr>
    </table>
</div>

CSS

#container {position: relative;}
table tr td{border:1px solid black;}
.first {position: relative; height:50px; width:100px;}
.second {width:150px;}

.indicator {
    position:absolute; 
    top:0px;
    left:0px;
    width:10px; 
    height:50px; 
    background-color:green;
}