JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
        <div class="sidebar">
            Sidebar
        </div>
        <div class="container">
            <div class="box">
                Height1
            </div>
            <div class="box">
                Height2<br />
                Height2
            </div>
            <div class="box">
                Height3<br />
                Height3<br />
                Height3
            </div>
            <div class="box">
                Height1
            </div>
            <div class="box">
                Height2<br />
                Height2
            </div>
            <div class="box">
                Height3<br />
                Height3<br />
                Height3
            </div>
        </div>
        <div class="sidebar">
            Sidebar
        </div>
    </div>

CSS

body {
    background: #bbb;
}

.wrap {
    background: #aaa;
    margin: 0 auto;
    display: block;
    overflow: hidden;
    width:661px;
}

.sidebar {
    width: 200px;
    float: left;
    background: #eee;
}

.container {
    margin: 0 auto;
    background: #ddd;
    display: block;
    float: left;
    padding: 5px;
}

.box {
    background: #eee;
    border: 1px solid #ccc;
    padding: 10px;
    margin: 5px;
    float: left;
}

.box:nth-child(3n+1) {
    clear: left;
}