body  { background-color: #f7f7f7; margin: 0; padding: 0 }


#ContainerDiv
 { background: #123456 url("img/bgstreifen1.gif"); text-align: center; margin-top: -238px; position: absolute; top: 50%; width: 100%; height: 476px }

#MainDiv {

 position : absolute;
 width : 776px;
 height : 476px;
 left : 50%;
 top : 50%;
 margin-left : -388px;
 margin-top : -238px;
 background : #FFFFFF;
background-color: #f7f7f7;
}