JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div id="sideColumn"></div>
    <div id="mainColumn">
        <div class="test"></div>
        <div class="test"></div>
        <div class="test"></div>      
    </div> 
</div>

CSS

#container {
    width:500px;
    overflow:hidden;
    border:1px solid #CCC;
}
#sideColumn {
    padding:20px 0;
    float:left;
    width:200px;
    overflow:hidden;
    background:blue;
}
#mainColumn {
    padding:20px 0;
    float:right;
    width:300px;    
    background:yellow;
}
.test {
    width:250px;
    height:50px;
    margin:15px 25px;
    background:red;
}