body {
    overflow:hidden;
    margin: 0px;
}
 .demo { 
    position:relative; 
    margin:0 auto; 
    bottom: 85px; 
    left: 46.2%;
    display: block;
    z-index: 100;
    cursor: pointer;
}

  .demo img { 
    left: 0; 
    position:absolute; 
    top: 0; 
}

  .demo img.raz {opacity:0;filter:alpha(opacity=0);}
  .demo:hover img.raz {opacity:1;filter:alpha(opacity=100);}
  .demo:hover img.dva, .demo img.dva:hover {opacity:0;filter:alpha(opacity=0);}
  .demo img {
  -moz-transition: all 1s ease-in-out;
  -webkit-transition: all 1s ease-in-out;
  -o-transition: all 1s ease-in-out;
  transition: all 1s ease-in-out;
}

.vignette {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  box-shadow: 0 0 150px rgba(0,0,0,0.4) inset;
}