.bouton_nav_debut_l {background-image:url('../images/navs/composants/20_1_1.png');width:10px;height:26px;}
.bouton_nav_debut_c {background-image:url('../images/navs/composants/20_1_2.png');height:26px;}
.bouton_nav_debut_r {background-image:url('../images/navs/composants/20_1_3.png');width:10px;height:26px;}
.bouton_nav_milieu_l {background-image:url('../images/navs/composants/20_2_1.png');width:10px;height:26px;}
.bouton_nav_milieu_c {background-image:url('../images/navs/composants/20_2_2.png');height:26px;}
.bouton_nav_milieu_r {background-image:url('../images/navs/composants/20_2_3.png');width:10px;height:26px;}
.bouton_nav_fin_l {background-image:url('../images/navs/composants/20_3_1.png');width:10px;height:26px;}
.bouton_nav_fin_c {background-image:url('../images/navs/composants/20_3_2.png');height:26px;}
.bouton_nav_fin_r {background-image:url('../images/navs/composants/20_3_3.png');width:10px;height:26px;}