body
{
   width: 100%;
   margin: auto; 
   margin-top: 2px; 
   margin-bottom: 20px;
}

#en_tete
{
position : absolute;
   top : 0px;
   left : 0px;
   width: 100%;
   height: 11%;
   margin-bottom: 2px;
   border-style : ridge;
   overflow : hidden;
}

#principal
{
position : absolute;
   top: 11%;
   left : 0px;
   width: 100%;
   height: 89%;
   border-style : ridge;
   background-color : #ccffff;
   overflow-y:scroll;
   overflow-x:scroll;
  }