.down_arrow,.up_arrow{position:relative;background-repeat:repeat-y}body{padding-top:50px}.up_arrow{background-image:url(../gfx/up_arrow.png);animation:animate_up 2s linear infinite}.down_arrow{background-image:url(../gfx/down_arrow.png);animation:animate_down 2s linear infinite}@keyframes animate_up{from{background-position:0 0}to{background-position:0 -97px}}@keyframes animate_down{from{background-position:0 0}to{background-position:0 99px}}