JSFiddle - React, Tailwind, and code Playground

HTML

<div id="smallColumn">a</div>
<div id="fullColumn">b</div>
<div style="clear:both"></div>
<div id="bottomDiv">
    <div id="tab">Tab</div>
<hr />
DATA DATA DATA
</div>

CSS

#smallColumn
{
    float:left;
    width:100px;
    height:100px;
    background:#000;
    margin:5px;
}
#fullColumn
{
    float:left;
    width:200px;
    height:300px;
    background:#000;
    margin:5px;
}   
#bottomDiv
{
    position:relative;
}
#tab
{
    position:absolute;
    bottom:100%;
}