.tab_nav{
width:137px;
line-height:33px;
cursor:pointer;
height:33px;
float:left;
text-align:center;
background:url(image_one/tab_nav_bg.gif) no-repeat;
font-weight:bold;
}
.tab_nav_on{
color:#FFFFFF;
width:137px;
cursor:pointer;
float:left;
line-height:33px;
height:33px;
text-align:center;
background:url(image_one/tab_nav_bg_on.gif) no-repeat;
font-weight:bold;
}