JSFiddle - React, Tailwind, and code Playground

HTML

<body>	
		<div id="maincontainer">
			<div id="leftcolumn">left</div>

			<div id="contentwrapper">right</div>
		</div>
	</body>

CSS

body {
	margin: 0 auto;
	height: 100%;
}

#maincontainer {
    width:100%;
    height: 100%;
}

#leftcolumn {
    float:left;
    display:inline-block;
    width: 510px;
    height: 100%;
	background: orange;
}

#contentwrapper {
	position: fixed;
    float:left;
    display:inline-block;
    width: -moz-calc(100% - 510px);
    width: -webkit-calc(100% - 510px);
    width: calc(100% - 510px);
    height: 100%;
	background-color: red;
}