:root {
  --paper: #f7f0dd;
  --paper-edge: #e6dcc2;
  --ink: #2c2519;
  --ink-soft: #6a5d48;
  --desk: #3f3225;
  --page-w: 300px;
  --page-h: 400px;
  --turn-ms: 950ms;
}

* { box-sizing: border-box; }

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

body {
  background: radial-gradient(ellipse at 50% 40%, #5a4a37 0%, var(--desk) 60%, #2b2118 100%);
  color: var(--ink);
  font-family: 'Libre Baskerville', 'Iowan Old Style', 'Palatino Linotype', Palatino, 'Book Antiqua', Georgia, serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  -webkit-user-select: none;
  user-select: none;
  touch-action: pan-y;
}

#app {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

.book-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav {
  appearance: none;
  border: 0;
  background: rgba(255, 245, 220, 0.08);
  color: #e9dcc0;
  width: 40px;
  height: 64px;
  border-radius: 8px;
  font: 32px/1 serif;
  cursor: pointer;
  transition: background .2s, opacity .2s;
}
.nav:hover { background: rgba(255, 245, 220, 0.18); }
.nav:disabled { opacity: 0.2; cursor: default; }

/* ---------- The book ---------- */

.book {
  position: relative;
  height: var(--page-h);
  perspective: 2600px;
  cursor: pointer;
}
.book.spread { width: calc(var(--page-w) * 2); }
.book.single { width: var(--page-w); }

.page {
  position: absolute;
  top: 0;
  width: var(--page-w);
  height: 100%;
  background: var(--paper);
  overflow: hidden;
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.45);
}
.spread .page.left  { left: 0;  border-radius: 6px 0 0 6px; }
.spread .page.right { right: 0; border-radius: 0 6px 6px 0; }
.single .page.left  { display: none; }
.page.measure { left: 0; visibility: hidden; pointer-events: none; z-index: -1; box-shadow: none; }
.single .page.right { left: 0; border-radius: 4px 6px 6px 4px; }

/* spine shading */
.spread .page.left::before,
.spread .page.right::before,
.spread .leaf .face::before {
  content: "";
  position: absolute;
  top: 0; bottom: 0;
  width: 12%;
  pointer-events: none;
  z-index: 2;
}
.spread .page.left::before,
.spread .leaf.back .face.front::before,
.spread .leaf.fwd .face.back::before {
  right: 0;
  background: linear-gradient(to left, rgba(60, 40, 10, 0.22), rgba(60, 40, 10, 0) 100%);
}
.spread .page.right::before,
.spread .leaf.fwd .face.front::before,
.spread .leaf.back .face.back::before {
  left: 0;
  background: linear-gradient(to right, rgba(60, 40, 10, 0.22), rgba(60, 40, 10, 0) 100%);
}

/* paper texture */
.page::after, .leaf .face::after {
  content: "";
  position: absolute; inset: 0;
  pointer-events: none;
  background:
    repeating-linear-gradient(0deg, rgba(120, 90, 40, 0.025) 0 2px, transparent 2px 5px),
    radial-gradient(ellipse at 30% 20%, rgba(255,255,255,0.35), transparent 60%);
  z-index: 1;
}

/* ---------- Page content ---------- */

.page-content {
  position: relative;
  z-index: 3;
  height: 100%;
  padding: calc(var(--page-w) * 0.10) calc(var(--page-w) * 0.10) calc(var(--page-w) * 0.15);
  font-size: calc(var(--page-w) * 0.046 * var(--fs-scale, 1));
  line-height: 1.6;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.9em;
  overflow: hidden;
  -webkit-user-select: text;
  user-select: text;
  cursor: text;
}
.page-content p { margin: 0; text-indent: 0; }
.page-content p + p { margin-top: 0; }
.page-content a { color: inherit; text-decoration: underline; text-decoration-color: var(--ink-soft); text-underline-offset: 0.15em; cursor: pointer; }
.page-content a:hover { text-decoration-color: var(--ink); }
.leaf .page-content a, .page.measure .page-content a { cursor: default; }
.page-content.center { justify-content: center; text-align: center; }
.page-content.center p { text-indent: 0; }

.page-content figure {
  margin: 0;
  flex: 0 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35em;
}
.page-content figure img {
  max-width: 100%;
  min-height: 0;
  max-height: calc(var(--page-h) * 0.72);
  object-fit: contain;
  display: block;
}
.page-content.has-text figure img { max-height: calc(var(--page-h) * 0.42); }
.page-content.image-only figure { flex: 1 1 auto; justify-content: center; }
.page-content figcaption {
  font-style: italic;
  font-size: 0.8em;
  color: var(--ink-soft);
  text-align: center;
}
.page-content .missing {
  border: 2px dashed #b9a98a;
  color: var(--ink-soft);
  font-size: 0.7em;
  padding: 1em;
  text-align: center;
  border-radius: 6px;
  width: 80%;
  word-break: break-all;
}
/* Text is selectable so readers can copy it; keep the turning leaf and the
   hidden measuring page inert. */
.leaf .page-content, .page.measure .page-content {
  -webkit-user-select: none;
  user-select: none;
  cursor: default;
}

/* cover / chapter / special pages */
.page-content.cover, .page-content.chapter {
  justify-content: center;
  align-items: center;
  text-align: center;
}
.page-content.cover .title {
  font-size: 1.7em;
  font-weight: 700;
  line-height: 1.25;
  margin: 0;
}
.page-content.cover .author, .page-content.cover .artist {
  font-style: italic;
  color: var(--ink-soft);
  margin: 0;
}
.page-content.cover .artist { font-size: 0.85em; }
.page-content.cover figure img { max-height: calc(var(--page-h) * 0.4); }
.page-content.cover .rule, .page-content.chapter .rule {
  width: 30%;
  border: 0;
  border-top: 1px solid #b09c78;
  margin: 0.2em 0;
}
.page-content.chapter h2 {
  font-size: 1.45em;
  font-weight: 400;
  margin: 0;
  line-height: 1.3;
}
.page-content.chapter .kicker {
  font-size: 0.7em;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.page-content.contents h2 {
  font-size: 1.2em;
  font-weight: 400;
  text-align: center;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin: 0 0 0.5em;
}
.page-content.contents ol {
  list-style: none;
  padding: 0; margin: 0;
  display: flex; flex-direction: column; gap: 0.5em;
}
.page-content.contents li {
  display: flex;
  align-items: baseline;
  gap: 0.4em;
  cursor: pointer;
}
.page-content.contents li:hover .name { text-decoration: underline; }
.page-content.contents .dots {
  flex: 1;
  border-bottom: 1px dotted #a8977a;
  transform: translateY(-0.3em);
}

.page-number {
  position: absolute;
  bottom: calc(var(--page-w) * 0.045);
  left: 0; right: 0;
  text-align: center;
  font-size: calc(var(--page-w) * 0.036);
  color: var(--ink-soft);
  z-index: 3;
}

/* ---------- Turning leaf ---------- */

.leaf {
  position: absolute;
  top: 0;
  width: var(--page-w);
  height: 100%;
  transform-style: preserve-3d;
  transition: transform var(--turn-ms) cubic-bezier(0.42, 0.05, 0.3, 1);
  z-index: 10;
  will-change: transform;
}
.leaf .face {
  position: absolute; inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  background: var(--paper);
  overflow: hidden;
}
.leaf .face.back { transform: rotateY(180deg); }

.spread .leaf.fwd  { right: 0; transform-origin: left center; }
.spread .leaf.back { left: 0;  transform-origin: right center; }
.spread .leaf.fwd  .face.front { border-radius: 0 6px 6px 0; }
.spread .leaf.fwd  .face.back  { border-radius: 6px 0 0 6px; }
.spread .leaf.back .face.front { border-radius: 6px 0 0 6px; }
.spread .leaf.back .face.back  { border-radius: 0 6px 6px 0; }
.spread .leaf.fwd.go  { transform: rotateY(-180deg); }
.spread .leaf.back.go { transform: rotateY(180deg); }

.single .leaf { left: 0; transform-origin: left center; border-radius: 4px 6px 6px 4px; }
.single .leaf .face { border-radius: 4px 6px 6px 4px; }
.single .leaf.fwd.go { transform: rotateY(-92deg); }
.single .leaf.back { transform: rotateY(-92deg); }
.single .leaf.back.go { transform: rotateY(0deg); }

/* shadow that the moving leaf casts */
.leaf .shade {
  position: absolute; inset: 0;
  pointer-events: none;
  z-index: 4;
  opacity: 0;
  transition: opacity calc(var(--turn-ms) * 0.5) ease-in;
  background: linear-gradient(to right, rgba(0,0,0,0.0), rgba(0,0,0,0.28));
}
.leaf.fwd .face.front .shade { background: linear-gradient(to left, rgba(0,0,0,0), rgba(0,0,0,0.3)); }
.leaf.go .face.front .shade { opacity: 1; }

/* ---------- Status ---------- */

.status {
  color: #cdbfa4;
  font-size: 13px;
  letter-spacing: 0.04em;
  opacity: 0.85;
  min-height: 1.2em;
  text-align: center;
}
.status .title { font-style: italic; }
.status .sep { margin: 0 0.6em; opacity: 0.5; }

@media (max-width: 520px) {
  .nav { display: none; }
  .book-wrap { gap: 0; }
}