JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
</head>
<body>
<div id="Div1">Div1</div>
<div id="Div2">Div2</div>
<div id="Div3">Div3</div>
</body>
</html>

CSS

Body
        {
            border:4px solid Black;
        }
        #Div1
        {
            border:4px solid Red;
            float:left;
        }
        #Div2
        {
            border:4px solid Red;
            float:right;
        }
        #Div3
        {
            border:4px solid Blue;
            width:640px;
            margin:auto;
        }