ul#barre_nav{
  width: 45em;
  margin :0px;
  padding: 0px;
  list-style: none;
  color: #000;}
   
  ul#barre_nav a{
  color: #000;
  text-decoration: none;}

  ul#barre_nav>li{  
  float: left;  
  width: 8em;
  margin-right: 0.4em;
  font-size: 1.1em;
  line-height:1.4em;
  background-color: #21b3ff; 
  text-align: center;}
  
  ul ul {
  display: none;
  position: absolute;  
  margin: 0px;
  padding: 0px;} 
  
  ul.niv3{
  position: absolute;
  left:140px;
  top: 0px;
  width: 10em;
  background-color: #afa;
  list-style-type: none;}
  
  ul.niv31{
  position: absolute;
  left:140px;
  top: 26.1px;
  width: 9em;
  background-color: #afa;
  list-style-type: none;}  
  
  ul.niv4{
  position: absolute;
  left:140px;
  bottom: 0px;
  width: 9em;
  background-color: #afa;
  list-style-type: none;}
    
  .niv2 {
  list-style-type: none; 
  width: 8em;
  background-color: #ff0;}
  
  #barre_nav ul.niv2>li:hover{
  background-color: #ffffce;}  
  
  ul.niv3>li:hover{
  background-color: #ceffce;}
  
  ul.niv31>li:hover{
  background-color: #ceffce;} 
  
  ul.niv4>li:hover{
  background-color: #ceffce;}
    
  li:hover ul.niv2,li li:hover ul.niv3,
  li li:hover ul.niv31,li li:hover ul.niv4
  {display:block;}