ul.AspNet-Menu{width:100%;} /* Avec les modifications, on définit juste la taille. Le reste se fait tout seul :D */

ul.AspNet-Menu{position: relative;}
ul.AspNet-Menu, 
ul.AspNet-Menu ul{margin: 0;padding: 0;display: block;}
ul.AspNet-Menu li{position: relative;list-style: none;float: left;}
ul.AspNet-Menu li a,
ul.AspNet-Menu li span{display: block;text-decoration: none;}
ul.AspNet-Menu ul{position:absolute;display:none;}

/* Add more rules here if your menus have more than three (3) tiers */
ul.AspNet-Menu li:hover ul ul,
ul.AspNet-Menu li:hover ul ul ul,
ul.AspNet-Menu li:hover ul ul ul ul,
ul.AspNet-Menu li.AspNet-Menu-Hover ul ul,
ul.AspNet-Menu li.AspNet-Menu-Hover ul ul ul,
ul.AspNet-Menu li.AspNet-Menu-Hover ul ul ul ul{display:none;}

/* Add more rules here if your menus have more than three (3) tiers */
ul.AspNet-Menu li:hover ul,
ul.AspNet-Menu li li:hover ul,
ul.AspNet-Menu li li li:hover ul,
ul.AspNet-Menu li li li li:hover ul,
ul.AspNet-Menu li li li li li:hover ul,
ul.AspNet-Menu li.AspNet-Menu-Hover ul,
ul.AspNet-Menu li li.AspNet-Menu-Hover ul,
ul.AspNet-Menu li li li.AspNet-Menu-Hover ul,
ul.AspNet-Menu li li li li.AspNet-Menu-Hover ul,
ul.AspNet-Menu li li li li li.AspNet-Menu-Hover ul{display:block;z-index:1;}

.AspNet-Menu-Vertical ul.AspNet-Menu li{width: 100%;}
ul.AspNet-Menu li{background:White;}
ul.AspNet-Menu ul li{margin-top:-1px;}

/* Menu Vertical */
ul.AspNet-Menu ul{width:100%;top:100%;left:0;}
ul.AspNet-Menu ul ul{top:1px;left:100%;margin-left:-1px;}
.sidebar ul.AspNet-Menu ul{width:100%;top:100%;right:0;}
.sidebar ul.AspNet-Menu ul ul{top:1px;left:-99%;margin-right:-1px;}

/* all anchors and spans (nodes with no link) */
ul.AspNet-Menu a, 
ul.AspNet-Menu span{padding:4px 2px 4px 8px;color:#797979;border:#e0e0e0 1px solid;background:#ffffff url(Images/ArrowRight.gif) right center no-repeat;}
ul.AspNet-Menu a{cursor:pointer;}
ul.AspNet-Menu span{cursor:default;}

/* leaves */
ul.AspNet-Menu li.AspNet-Menu-Leaf a, 
ul.AspNet-Menu li.AspNet-Menu-Leaf span{background-image: none !important;}

/* hovered text */
ul.AspNet-Menu li:hover a, 
ul.AspNet-Menu li:hover span,
ul.AspNet-Menu li.AspNet-Menu-Hover a,
ul.AspNet-Menu li.AspNet-Menu-Hover span,
ul.AspNet-Menu li:hover li:hover a,
ul.AspNet-Menu li:hover li:hover span,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover a,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover span,
ul.AspNet-Menu li:hover li:hover li:hover a,
ul.AspNet-Menu li:hover li:hover li:hover span,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover a,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover span,
ul.AspNet-Menu li:hover li:hover li:hover li:hover a,
ul.AspNet-Menu li:hover li:hover li:hover li:hover span,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover a,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover span
{color:White;background:#f4831f url(Images/ArrowRight.gif) right center no-repeat;}

/* the tier above this one is hovered */
ul.AspNet-Menu li:hover li a, 
ul.AspNet-Menu li:hover li span,
ul.AspNet-Menu li.AspNet-Menu-Hover li a,
ul.AspNet-Menu li.AspNet-Menu-Hover li span,
ul.AspNet-Menu li:hover li:hover li a,
ul.AspNet-Menu li:hover li:hover li span,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li a,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li span,
ul.AspNet-Menu li:hover li:hover li:hover li a,
ul.AspNet-Menu li:hover li:hover li:hover li span,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover li a,
ul.AspNet-Menu li.AspNet-Menu-Hover li.AspNet-Menu-Hover li.AspNet-Menu-Hover li span
{color:#797979;background:#ffffff url(Images/ArrowRight.gif) right center no-repeat;}

/* this tier is selected */
ul.AspNet-Menu .AspNet-Menu-Selected{background-color:#daebf5;}

/* a tier below this one is selected */
ul.AspNet-Menu .AspNet-Menu-ChildSelected{background:#daebf5 url(Images/arrowRight.gif) right center no-repeat;}

/* a tier above this one is selected */
ul.AspNet-Menu .AspNet-Menu-ParentSelected {}