JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="sidebar"></div>
<div class="right"></div>
</div>

CSS

body {
    margin: 0;
}

.container {
    width: 100%;
}

.sidebar {
    opacity: 0.7;
    position: fixed;
    background-color: tomato;
    width: 35%;
    height: 400px;
}

.right {
    background: url('http://farm7.staticflickr.com/6212/6365239995_8f5d03fb30_b.jpg') no-repeat fixed;
    height: 400px;
}