.nav_up{
    padding:7px;
    background-color:white;
    border:1px solid #CCC;
    position:fixed;
    background:transparent url(../images/arrow_up.png) no-repeat top left;
    background-position:50% 50%;
    width:20px;
    height:20px;
    bottom:10px;
    opacity:0.7;
    left:30px;
    white-space:nowrap;
    cursor: pointer;
    -moz-border-radius: 3px 3px 3px 3px;
    -webkit-border-top-left-radius:3px;
    -webkit-border-top-right-radius:3px;
    -khtml-border-top-left-radius:3px;
    -khtml-border-top-right-radius:3px;
    filter:progid:DXImageTransform.Microsoft.Alpha(opacity=70);
}
.nav_down{
    padding:7px;
    background-color:white;
    border:1px solid #CCC;
    position:fixed;
    background:transparent url(../images/arrow_down.png) no-repeat top left;
    background-position:50% 50%;
    width:20px;
    height:20px;
    bottom:10px;
    opacity:0.7;
    left:70px;
    white-space:nowrap;
    cursor: pointer;
    -moz-border-radius: 3px 3px 3px 3px;
    -webkit-border-top-left-radius:3px;
    -webkit-border-top-right-radius:3px;
    -khtml-border-top-left-radius:3px;
    -khtml-border-top-right-radius:3px;
    filter:progid:DXImageTransform.Microsoft.Alpha(opacity=70);
}