JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
    <HTML>
    <HEAD>
    <style>
    #boxTop{
        margin-bottom:20px;
        border:1px solid green;
    }
    #box1{
        float:left;
        border:1px solid blue;
    }
    #box2{
        clear:left;
        border:1px solid red;
        min-height: 0;
    }
    </style>
    </HEAD>
    <BODY>
    <div id="boxTop">test</div>
    <div id="box1">test</div>
    <div id="box2">bottom</div>
    </BODY>
    </HTML>