.header
{
    width:736px;
    margin-left: auto;
    margin-right: auto;
}
.main_bg
{    
    height:510px;
    background-image: url('../Images/bg.gif');
    background-repeat:repeat-x;
    margin-left: auto;
    margin-right: auto;
}
 .main_bg1
{
    margin:auto;
    width:735px;
    height:510px;
    background-image: url('../Images/bg1.gif');
    background-repeat:no-repeat;    
}
.main
{
    width:665px;
    height:500px;
    margin:auto;
}

 .down
{
    width:736px;
    margin-left: auto;
    margin-right: auto;
}