JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootswatch/3.0.0/united/bootstrap.min.css">
<div>
		<div id="sidebar">
			<ul>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
				<li>A</li>
			</ul>
		</div>
		<div id="main">
			<div class="clearfix">
				<div class="pull-right">
					<a>FOO</a>
				</div>
			</div>
			<div>Hello</div>
		</div>
	</div>

CSS

#sidebar {
			background: red;
			float: left;
			width: 100px;
		}
		
		#main {
			background: green;
			margin-left: 150px;
		}