body { background: #ffffff url(../img/body_bg_wood.jpg); text-align: center; }#tab_3 { z-index: 5; top: 220px; }
#tab_3_btn_box { z-index: 6; top: 220px; }
#tab_2 { z-index: 102; top: 336px; }
#tab_2_btn_box { z-index: 103; top: 336px; }
#tab_1 { z-index: 1; top: 496px; }
#tab_1_btn_box { z-index: 2; top: 496px; }
#nav_1_menu { display: none; }
#nav_2_menu { display: block; }
#nav_3_menu { display: none; }