JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="http://malsup.github.com/jquery.cycle2.js"></script>
<div id="background" class="cycle-slideshow" data-cycle-fx="scrollHorz" data-cycle-timeout="2000" data-cycle-slides="> div">
    <div style="background:#fcc">
        <img src="http://stoptraining.me/staged/IMG_1402.jpg">
    </div>
    <div style="background:#cfc">
        <img src="http://stoptraining.me/staged/IMG_1403.jpg">
    </div>
</div>
<div class="center">
    <div id="log"></div>
    <div id="text" class="cycle-slideshow" data-cycle-fx="fade" data-cycle-timeout="2000" data-cycle-slides="> div">
        <div>
            <h2>Title</h2>
            <p>Lorem ipsum dolor ...</p>
        </div>
        <div>
            <p>Mel eu pertinax ...</p>
        </div>
        <div>
            <p>Utinam electram pertinacia ...</p>
        </div>
    </div>
</div>

CSS

/* Eric Meyer's Reset Reloaded */

/* http://meyerweb.com/eric/thoughts/2007/05/01/reset-reloaded/ */
 html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td {
    margin: 0;
    padding: 0;
    border: 0;
    outline: 0;
    font-size: 100%;
    vertical-align: baseline;
    background: transparent;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
/* remember to define focus styles! */
 :focus {
    outline: 0;
}
/* remember to highlight inserts somehow! */
 ins {
    text-decoration: none;
}
del {
    text-decoration: line-through;
}
/* tables still need 'cellspacing="0"' in the markup */
 table {
    border-collapse: collapse;
    border-spacing: 0;
}
body, html {
    background: red;
    padding:0;
    margin:0;
    height:auto;
    width: 100%;
}
#background {
    position: fixed;
    width: 100%;
    height: 100%;
    z-index: 99;
    overflow: hidden;
}
#background div {
    width: 100%;
    height: 100%;
    background-size:cover;
    overflow: hidden;
}
#text {
    position: relative;
    text-align: center;
    z-index: 99;
}
.center {
    background: white;
    padding: 200px 0 0 0;
    width: 400px;
    overflow: auto;
    min-height: 1000px;
    margin: auto;
    z-index: 9999;
    position: relative;
    text-align: center;
}
#background div img.wider {
    width: 100%;
    height: auto;
}
#background div img.higher {
    width: auto;
    height: 100%;
}

JavaScript

var imgWidth = 1600;
var imgHeight = 1067;
var imgRatio = imgWidth / imgHeight;

$(ResizeBackground); // call on initialize
$(window).resize(ResizeBackground); // and on resize

function ResizeBackground() {
    var div = $('#background');
    var divWidth = div.width();
    var divHeight = div.height();

    if (divWidth / divHeight > imgRatio) {
        div.find('img').removeClass('higher').addClass('wider');
    } else {
        div.find('img').removeClass('wider').addClass('higher');
    }
}