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:right;}
ul.AspNet-Menu li li{float:right;}
ul.AspNet-Menu li a,
ul.AspNet-Menu li span{display: block;text-decoration: 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;}

ul.AspNet-Menu li{height:24px;background:url(Images/Menu/bg-tab-off-left.gif) no-repeat left top;padding-left:6px;margin-right:5px;}
html>body ul.AspNet-Menu li{background:url(Images/Menu/bg-tab-off-left.png) no-repeat left top;}
ul.AspNet-Menu ul{width:197px;padding:1px;background:White;border:#d6d6d6 1px solid;position:absolute;top:100%;right:0;display:none;}
ul.AspNet-Menu ul li{width:100%;height:auto;padding:0;margin:0;text-align:right;background:none !important;}
ul.AspNet-Menu ul a,
ul.AspNet-Menu ul span{line-height:20px;padding:0 8px !important;font-size:12px;font-weight:normal;font-style:normal;background:none !important;color:#d65337;}

ul.AspNet-Menu ul ul{top:-2px;right:197px;}
.menu ul.AspNet-Menu ul ul{top:-2px;left:197px;}

/* all anchors and spans (nodes with no link) */
ul.AspNet-Menu a, 
ul.AspNet-Menu span{font-size:13px;font-weight:bold;font-style:normal;color:White;padding:4px 10px 4px 4px;background:url(Images/Menu/bg-tab-off-right.gif) no-repeat right top;}
html>body ul.AspNet-Menu a, 
html>body ul.AspNet-Menu span{background:url(Images/Menu/bg-tab-off-right.png) no-repeat right top;}

/* hovered text */
ul.AspNet-Menu li.AspNet-Menu-Hover,
ul.AspNet-Menu li:hover{background:url(Images/Menu/bg-tab-on-left.gif) no-repeat left top;padding-left:6px;}
html>body ul.AspNet-Menu li:hover{background:url(Images/Menu/bg-tab-on-left.png) no-repeat left top;}
ul.AspNet-Menu ul li.AspNet-Menu-Hover,
ul.AspNet-Menu ul li:hover{width:100%;padding:0;margin:0;text-align:right;background:#d65336 !important;}
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
{color:#d65337;background:url(Images/Menu/bg-tab-on-right.gif) no-repeat right top;padding:4px 10px 4px 4px;}
html>body ul.AspNet-Menu li:hover a, 
html>body ul.AspNet-Menu li:hover span,
html>body ul.AspNet-Menu li.AspNet-Menu-Hover a,
html>body ul.AspNet-Menu li.AspNet-Menu-Hover span
{background:url(Images/Menu/bg-tab-on-right.png) no-repeat right top;}
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
{line-height:20px;color:White;background:none !important;padding:0 8px;font-size:12px;font-weight:normal;font-style:normal;margin:0;}

/* 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: #d65337;background: transparent url(Images/Menu/arrowRight.gif) right center no-repeat;}