JSFiddle - React, Tailwind, and code Playground

HTML

<div id="frm">
       <div id="a">aaa<br>aaa</div>
       <div id="b">bbb</div>
    </div>

CSS

#frm {
    background: red;
    width: 100%;
    height: auto;
}

#a {
    background: blue;
    float: left;    
}

#b {
    background: green;
    float: right;
}