/* Scroll-driven reader (index.html): the book stays fixed while scrolling turns pages. */
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans)}
.viewport{position:fixed;inset:0;display:flex;flex-direction:column}
html,body{height:100%;overflow:hidden;overscroll-behavior:none}
.stage{touch-action:none}
.stage{position:relative;flex:1;min-height:0;overflow:hidden;display:grid;place-items:center;padding:8px 12px}
.spread{position:relative;perspective:2600px}
.leaf{position:absolute;top:0;left:50%;width:50%;height:100%;transform-origin:left center;transform-style:preserve-3d;will-change:transform}
.spage{position:absolute;inset:0;transform-origin:left center;backface-visibility:hidden;-webkit-backface-visibility:hidden;will-change:transform,opacity}