.nav_up{padding:7px;position:fixed;background:transparent url(images/arrow_up.png) no-repeat top left;background-position:50% 50%;width:30px;height:30px;bottom:25px;right:30px;white-space:nowrap;cursor:pointer;z-index:2;}
.nav_up:hover{background:transparent url(images/arrow_up_hover.png) no-repeat 50% 50%;}
.nav_down{padding:7px;position:fixed;background:transparent url(images/arrow_down.png) no-repeat top left;background-position:50% 50%;width:20px;height:20px;bottom:10px;right:65px;white-space:nowrap;cursor:pointer;}