gistfile1.css

.original-background{    
    background:url(http://img850.imageshack.us/img850/2400/rowofstars.gif) repeat;
}

.diagonal-background:before{
    content:"";
    background:url(http://img850.imageshack.us/img850/2400/rowofstars.gif) repeat;
    width:200%;
    height:200%;
    position:absolute;
    top:0px;
    left:0px;
    z-index:-1;
    -webkit-transform:rotate(-13deg) translate(10px,-220px); 
    -moz-transform:rotate(-13deg) translate(10px,-220px); 
    -o-transform:rotate(-13deg) translate(10px,-220px); 
    -ms-transform:rotate(-13deg) translate(10px,-220px); 
}

.diagonal-background{
    overflow:hidden;
}