JSFiddle - React, Tailwind, and code Playground

HTML

<div id='topbar'>
</div><!--topbar-->

<div id='center_background'>
</div>

CSS

body
{
background:url('http://4.bp.blogspot.com/-34oIfGrFSNM/UCtwzuHoZVI/AAAAAAAACPo/n1wV8U3bMAY/s1600/light_gray_background.jpg');
}

#topbar
{
background:rgba(150,0,0,1);

position:absolute;
display:block;
float:left;
top:0;
width:100%;
height:80px;
margin-top:0%;

border-top: 0px solid rgba(0,0,0,0.3);
border-bottom: 2px solid rgba(0,0,0,0.3);

}

div#center_background
{
position:absolute;
    z-index:-1;
top:0px;
left:20%; 
width:60%;
height:200%;

background:rgba(255,255,255,0.9);
}