JSFiddle - React, Tailwind, and code Playground

HTML

<div class="row">
        <div class="col-xs-9">
            <div class="left-side">
                <p>sdfsdf</p>
                <p>sdfsdf</p>
               <p>sdfsdf</p>
            </div>
        </div>
        <div class="col-xs-3">
            <div class="something">asdfdf</div>
        </div>
    </div>

CSS

@import url('http://getbootstrap.com/dist/css/bootstrap.css');

.left-side {
    background-color: blue;
    padding-bottom: 1000px;
    margin-bottom: -1000px;
    height: 100%;
}
.something {
    height: 100%;
    background-color: red;
    padding-bottom: 1000px;
    margin-bottom: -1000px;
    height: 100%;
}
.row {
    background-color: green;
    overflow: hidden;
}