0&&Math.abs(h-lastH)>1){lastH=h;f.style.height=h+'px';}follow();}
function follow(){if(!d)return;var r=f.getBoundingClientRect(),vh=window.innerHeight;
if(bar){var bh=bar.offsetHeight,vis=Math.min(vh,r.bottom)-r.top;var t=Math.max(0,Math.min(vis-bh,lastH-bh));bar.style.top=t+'px';}
if(stage&&grid){var off=0;if(false){var g=grid.getBoundingClientRect(),sh=stage.offsetHeight,bh=bar?bar.offsetHeight:0,fw=d.querySelector('.footwrap'),room=g.height-sh-(fw?fw.offsetHeight:0);off=(sh