JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
<div id="navBar" class="big"></div>
<div id="content" class="big"></div>
</div>

CSS

.big{
    height:100px;
}
#navBar{
    float: left;
    background-color:#666;
    width:300px;
}
#content{
    background-color:#999;
    margin-left: 310px;
    height: 400px;
}