.menu_a {
     list-style: none;
     position: relative;
     margin: 0;
     padding: 0;
}
.menu_a li {
    display: block;
    overflow: hidden;
    padding: 0;
    cursor: pointer;
	float: left;
	width: 160px;
	height:30px;
	margin-right: 0px;
}
.menu_a a {
	display:block;
	height:30px;
	line-height: 30px;
	text-indent:10px;
	outline:none;
	text-decoration:none;
	font-size: 12px; color: #ffffff; font-family: Arial, Helvetica, sans-serif
}
.menu_a a:hover {
	color:#003051;
	font-weight:bold;
	text-decoration:none;
}

li.a1 a {background-image:url(images/header/bt_haut_0.gif);}
li.a2 a, li.a3 a, li.a4 a {background-image:url(images/header/bt_haut_1.gif);}
li.a5 a, li.a6 a {background-image:url(images/header/bt_haut_2.gif);}

li.a1 a:hover {background-image:url(images/header/bt_over_0.gif);}
li.a2 a:hover, li.a3 a:hover, li.a4 a:hover {background-image:url(images/header/bt_over_1.gif);}
li.a5 a:hover, li.a6 a:hover {background-image:url(images/header/bt_over_2.gif);}

li.b1 a {background-image:url(images/header/bt_haut_30.gif);}
li.b2 a, li.b3 a {background-image:url(images/header/bt_haut_3.gif);}
li.b4 a, li.b5 a {background-image:url(images/header/bt_haut_4.gif);}
li.b6 a {background-image:url(images/header/bt_haut_5.gif);}

li.b1 a:hover {background-image:url(images/header/bt_over_30.gif);}
li.b2 a:hover, li.b3 a:hover {background-image:url(images/header/bt_over_3.gif);}
li.b4 a:hover, li.b5 a:hover {background-image:url(images/header/bt_over_4.gif);}
li.b6 a:hover {background-image:url(images/header/bt_over_5.gif);}