JSFiddle - React, Tailwind, and code Playground

HTML

<div class="vbox">
    <img id="bg" src="http://dl.dropbox.com/u/2402301/cyberman.jpg" />
    <div class="content">
        <p>Qualquer conteudo</p>
    </div>
</div>

CSS

body,html{
    height: 100%;
    margin: 0;
    padding: 0;
}

.vbox{
    height: 100%;
    text-align: center;
    white-space: nowrap;
}

.vbox:before{
    content: "";
    display: inline-block;
    vertical-align: middle;
    width: 0;
    margin-right: -.25em;
    height: 100%;
}

#bg {
    position: fixed;
    top:  0;
    left: 0;
    width: 100%;
    height: 100%;
    position:absolute;
    z-index:-1;
}

.content {
    border: 2px solid white ;
    display: inline-block;
    vertical-align: middle;
    white-space: normal;
    padding: 0 1em;
    background: #EEE;
    width: 50%;
    height: 50%;
    position: static;
    z-index: 1;
}