in the screen.css file, remove the background-color: #fff attribute from the html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6 { selector:
html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6 {
margin: 0;
border: 0;
outline: 0;
font-size: 100%;
/*background-color: #FFF;*/
}