html { height:100%; }
body { margin:0;padding:0;height:100%; }

.viewport { overflow:hidden; }
.viewport iframe { width:100%;height:100%;border:0 none;overflow:hidden; }

.move-up, .move-down { overflow:hidden;width:100%;height:20px;background:#b9cad1 url(../images/scroll-controls.png) center -99px no-repeat; }
.move-up-visible { background-position:center top;cursor:pointer; }
.move-down-visible { background-position:center bottom;cursor:pointer;}