JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<div class="row">
  <div class="col-xs-3"><div id="sidebar">sidebar</div></div>
  <div class="col-xs-3">content content content content content content content content content content content content content content content</div>
</div>

CSS

.row {
        display: table;
    }
    
    [class*="col-"] {
        float: none;
        display: table-cell;
        vertical-align: top;
        background: #ccc;
        color: #fff;
        border: 1px solid #fff;
    }