JSFiddle - React, Tailwind, and code Playground

HTML

<div id="page">
<div id="sidecolumn">
</div>
<div id="maincolumn">
    <div id="content">
    contents
    </div>
</div>

</div>

CSS

#content {
    background: #EEE;
    font: 1.5em arial, verdana, sans-serif;
    display:table-cell;
}

#sidecolumn {
    width: 500px;
    background: #000;
    display:table-cell;
    }

#maincolumn {
    height: 100%;

    }

#page {
    height: 100%;
  display:table;
    }