div.topo ul.menus img.bt1{	background-image: url(img/pt/bt_01-off.gif);}div.topo ul.menus img.bt1:hover, img.bt1_on {	background-image: url(img/pt/bt_01-on.gif);}div.topo ul.menus img.bt2{	background-image: url(img/pt/bt_02-off.gif);}div.topo ul.menus img.bt2:hover, img.bt2_on  {	background-image: url(img/pt/bt_02-on.gif);}div.topo ul.menus img.bt3{	background-image: url(img/pt/bt_03-off.gif);}div.topo ul.menus img.bt3:hover, img.bt3_on  {	background-image: url(img/pt/bt_03-on.gif);}div.topo ul.menus img.bt4{	background-image: url(img/pt/bt_04-off.gif);}div.topo ul.menus img.bt4:hover, img.bt4_on  {	background-image: url(img/pt/bt_04-on.gif);}div.topo ul.menus img.bt5{	background-image: url(img/pt/bt_05-off.gif);}div.topo ul.menus img.bt5:hover, img.bt5_on  {	background-image: url(img/pt/bt_05-on.gif);}div.topo ul.menus img.bt6{	background-image: url(img/pt/bt_06-off.gif);}div.topo ul.menus img.bt6:hover, img.bt6_on  {	background-image: url(img/pt/bt_06-on.gif);}