.main_menu {
  background-image:url(img/bgm_swi.gif);
}
.menu_home {
 background-image:url(img/bgm_swi_home.gif);
}
.menu_leist {
 background-image:url(img/bgm_swi_leist.gif);
}
.menu_ref {
 background-image:url(img/bgm_swi_ref.gif);
}
.menu_mit {
 background-image:url(img/bgm_swi_mit.gif);
}
.menu_uns {
 background-image:url(img/bgm_swi_uns.gif);
}
.menu_kont {
 background-image:url(img/bgm_swi_kont.gif);
}