JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="bg">
        <div class="page">
            <div class="box"></div>
        </div>
    </div>
</body>

CSS

html {
    margin: 0;
    padding: 0;
    height: 100%;
}
body {
    margin: 0;
    padding 0;
    min-width: 300px;
    height: 100%;
}
.bg {
    min-height: 100%;
    background: url('http://s1.postimg.org/v6b86617j/bg_center.png') center top repeat-y;
}
.page {
    width: 200px;
    height: 300px;
    margin: 0 auto;
    position: relative;
}
.box {
    width: 50px;
    height: 50px;
    background: yellow;
}