/* ------------------------------------------------------------------
   eBook Studio viewer
   Dark-first, touch-first, zero dependencies.
------------------------------------------------------------------ */

:root {
  --accent: #e2001a;
  --bg: #0d0f11;
  --fg: #eef1f4;
  --muted: #9aa4ae;
  --chrome: rgba(18, 21, 24, .82);
  --line: rgba(255, 255, 255, .09);
  --hover: rgba(255, 255, 255, .09);
  --panel: #14181c;
  --shadow: 0 24px 60px rgba(0, 0, 0, .5);
  --bar-h: 52px;
  --radius: 12px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color-scheme: dark;
}

html[data-theme='light'] {
  --bg: #eceef1;
  --fg: #14181c;
  --muted: #5d6773;
  --chrome: rgba(255, 255, 255, .9);
  --line: rgba(0, 0, 0, .1);
  --hover: rgba(0, 0, 0, .06);
  --panel: #fff;
  --shadow: 0 20px 50px rgba(0, 0, 0, .18);
  color-scheme: light;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  overscroll-behavior: none;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

button { font-family: inherit; color: inherit; }

.viewer {
  position: fixed;
  inset: 0;
  display: grid;
  grid-template-rows: auto 1fr auto;
  /* A grid track is sized by its widest child unless told otherwise, so the
     page slider used to stretch the whole viewer past a narrow screen and push
     the last toolbar button off the edge. */
  grid-template-columns: minmax(0, 1fr);
  background: var(--bg);
}

/* ------------------------------------------------------------ bars */

.bar {
  display: flex;
  align-items: center;
  min-width: 0;
  gap: 8px;
  padding: 0 10px;
  height: var(--bar-h);
  background: var(--chrome);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  z-index: 30;
  transition: transform .28s cubic-bezier(.4, 0, .2, 1), opacity .28s;
}

.bar--top { border-bottom: 1px solid var(--line); }
.bar--bottom {
  border-top: 1px solid var(--line);
  padding-bottom: env(safe-area-inset-bottom);
  height: calc(var(--bar-h) + env(safe-area-inset-bottom));
}

.ui-hidden .bar--top { transform: translateY(-100%); opacity: 0; }
.ui-hidden .bar--bottom { transform: translateY(100%); opacity: 0; }
.ui-hidden .edge { opacity: 0; }

.bar__spacer { flex: 1; }

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  /* The title gives way before the buttons do: on a narrow screen the tools
     must all stay reachable, and a truncated title costs nothing. */
  flex: 0 1 auto;
  min-width: 0;
  overflow: hidden;
  padding-left: 4px;
}
.brand img { height: 24px; width: auto; display: block; }
.brand__title {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
  max-width: 34vw;
}
.brand__sub { font-size: 12px; color: var(--muted); }

.btn {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  cursor: pointer;
  transition: background .15s;
  flex: none;
}
.btn:hover { background: var(--hover); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn[aria-pressed='true'] { background: var(--hover); color: var(--accent); }
.btn svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.btn--wide { width: auto; padding: 0 14px; gap: 8px; grid-auto-flow: column; font-size: 13px; font-weight: 600; }
.btn--accent { background: var(--accent); color: #fff; }
.btn--accent:hover { background: var(--accent); filter: brightness(1.1); }
.btn:disabled { opacity: .3; cursor: default; }

/* ---------------------------------------------------------- stage */

.stage {
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: center;
  padding: 18px;
  touch-action: pan-y;
  min-height: 0;
}

.book {
  position: relative;
  display: flex;
  perspective: 2600px;
  perspective-origin: 50% 42%;
  will-change: transform;
  /* A lone cover or back page is centred; the shift animates so the book
     visibly opens and closes at the ends. */
  transition: transform .42s cubic-bezier(.32, .06, .24, 1);
}

.pane {
  position: relative;
  background: #fff;
  overflow: hidden;
  flex: none;
  box-shadow: 0 10px 40px rgba(0, 0, 0, .45);
}
html[data-theme='light'] .pane { box-shadow: 0 8px 30px rgba(0, 0, 0, .2); }

.pane img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: #fff;
  user-select: none;
  -webkit-user-drag: none;
}
/* Clicking a page magnifies it, so the pointer says so. */
.book--ready .pane:not(.pane--empty) { cursor: zoom-in; }
.hotspot { cursor: pointer; }
.pane--empty { background: transparent; box-shadow: none; }
.pane--empty img { visibility: hidden; }

/* The subtle inner gutter that makes two pages read as one book */
.book--spread .pane--left::after,
.book--spread .pane--right::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  width: 26px;
  pointer-events: none;
}
.book--spread .pane--left::after { right: 0; background: linear-gradient(to right, transparent, rgba(0,0,0,.16)); }
.book--spread .pane--right::after { left: 0; background: linear-gradient(to left, transparent, rgba(0,0,0,.16)); }

/* ----------------------------------------------------- page turn */

.turning {
  position: absolute;
  top: 0;
  transform-style: preserve-3d;
  will-change: transform;
  z-index: 5;
}
.turning--next { transform-origin: left center; }
.turning--prev { transform-origin: right center; }

.face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  overflow: hidden;
  background: #fff;
}
.face img { display: block; width: 100%; height: 100%; object-fit: contain; }
.face--back { transform: rotateY(180deg); }

.face__shade {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0;
}
.turning--next .face--front .face__shade { background: linear-gradient(to left, rgba(0,0,0,.5), transparent 60%); }
.turning--next .face--back  .face__shade { background: linear-gradient(to right, rgba(0,0,0,.55), transparent 60%); }
.turning--prev .face--front .face__shade { background: linear-gradient(to right, rgba(0,0,0,.5), transparent 60%); }
.turning--prev .face--prev  .face__shade { background: linear-gradient(to left, rgba(0,0,0,.55), transparent 60%); }

.book--sliding .pane { transition: transform .3s cubic-bezier(.33,.1,.2,1), opacity .3s; }

/* --------------------------------------------------------- hotspots */

.hotspots { position: absolute; inset: 0; }
.hotspot {
  position: absolute;
  display: block;
  border-radius: 4px;
  background: transparent;
  border: 0;
  cursor: pointer;
  transition: background .18s, box-shadow .18s;
  padding: 0;
}
.hotspot:hover, .hotspot:focus-visible {
  background: color-mix(in srgb, var(--accent) 22%, transparent);
  box-shadow: 0 0 0 2px var(--accent);
  outline: none;
}
.show-links .hotspot { background: color-mix(in srgb, var(--accent) 16%, transparent); }

.hitmark {
  position: absolute;
  border-radius: 3px;
  background: rgba(255, 214, 0, .45);
  box-shadow: 0 0 0 1px rgba(255, 214, 0, .8);
  animation: hitpulse 1.6s ease-out 2;
  pointer-events: none;
}
@keyframes hitpulse { 0%,100% { opacity: .25; } 50% { opacity: 1; } }

/* ------------------------------------------------------ edge arrows */

.edge {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 46px;
  height: 76px;
  border: 0;
  border-radius: 10px;
  background: var(--chrome);
  backdrop-filter: blur(10px);
  cursor: pointer;
  display: grid;
  place-items: center;
  opacity: .75;
  transition: opacity .2s, background .2s;
  z-index: 20;
}
.edge:hover { opacity: 1; background: var(--hover); }
.edge--prev { left: 10px; }
.edge--next { right: 10px; }
.edge svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.edge:disabled { opacity: 0; pointer-events: none; }

/* ------------------------------------------------------ bottom bar */

.pager { display: flex; align-items: center; gap: 12px; flex: 1; min-width: 0; }
.pager__label {
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  color: var(--muted);
  white-space: nowrap;
  min-width: 92px;
  text-align: center;
}
.pager__label b { color: var(--fg); font-weight: 600; }

.slider { -webkit-appearance: none; appearance: none; flex: 1; height: 22px; background: transparent; cursor: pointer; min-width: 60px; }
.slider::-webkit-slider-runnable-track { height: 4px; border-radius: 2px; background: var(--line); }
.slider::-moz-range-track { height: 4px; border-radius: 2px; background: var(--line); }
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%;
  background: var(--accent); margin-top: -5px; box-shadow: 0 1px 4px rgba(0,0,0,.4);
}
.slider::-moz-range-thumb { width: 14px; height: 14px; border: 0; border-radius: 50%; background: var(--accent); }

/* ---------------------------------------------------------- panels */

.panel {
  position: absolute;
  top: var(--bar-h);
  bottom: 0;
  left: 0;
  width: min(360px, 88vw);
  background: var(--panel);
  border-right: 1px solid var(--line);
  z-index: 40;
  display: flex;
  flex-direction: column;
  transform: translateX(-102%);
  transition: transform .26s cubic-bezier(.4, 0, .2, 1);
  box-shadow: var(--shadow);
}
.panel[data-open='true'] { transform: none; }
.panel--wide { width: min(560px, 96vw); }

.panel__head {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 10px 12px 16px;
  border-bottom: 1px solid var(--line);
}
.panel__title { font-size: 13px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); flex: 1; }
.panel__body { overflow: auto; padding: 8px 0 24px; flex: 1; -webkit-overflow-scrolling: touch; }

.toc-item {
  display: flex;
  gap: 10px;
  align-items: baseline;
  width: 100%;
  text-align: left;
  padding: 9px 16px;
  border: 0;
  background: transparent;
  cursor: pointer;
  font-size: 14px;
  line-height: 1.45;
}
.toc-item:hover { background: var(--hover); }
.toc-item[data-level='1'] { padding-left: 32px; font-size: 13.5px; color: var(--muted); }
.toc-item[data-level='2'] { padding-left: 48px; font-size: 13px; color: var(--muted); }
.toc-item__page { margin-left: auto; font-size: 12px; color: var(--muted); font-variant-numeric: tabular-nums; }
.toc-item[aria-current='true'] { color: var(--accent); font-weight: 600; }

.searchbar { display: flex; gap: 8px; padding: 12px 12px 12px 16px; border-bottom: 1px solid var(--line); }
.searchbar input {
  flex: 1; padding: 9px 12px; border-radius: 9px; font-size: 14px;
  border: 1px solid var(--line); background: color-mix(in srgb, var(--fg) 6%, transparent); color: var(--fg);
}
.searchbar input:focus { outline: 2px solid var(--accent); outline-offset: 0; border-color: transparent; }

.hit { display: block; width: 100%; text-align: left; padding: 11px 16px; border: 0; background: transparent; cursor: pointer; border-bottom: 1px solid var(--line); }
.hit:hover { background: var(--hover); }
.hit__page { font-size: 11px; text-transform: uppercase; letter-spacing: .07em; color: var(--accent); font-weight: 700; }
.hit__text { font-size: 13.5px; color: var(--muted); line-height: 1.5; margin-top: 3px; }
.hit__text mark { background: color-mix(in srgb, var(--accent) 30%, transparent); color: var(--fg); border-radius: 2px; padding: 0 1px; }

.empty-note { padding: 28px 20px; color: var(--muted); font-size: 13.5px; text-align: center; line-height: 1.6; }

/* ------------------------------------------------------ thumbnails */

.thumbs {
  position: absolute;
  inset: var(--bar-h) 0 0 0;
  background: color-mix(in srgb, var(--bg) 94%, transparent);
  backdrop-filter: blur(18px);
  z-index: 35;
  overflow: auto;
  padding: 20px;
  display: none;
}
.thumbs[data-open='true'] { display: block; }
.thumbs__grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(112px, 1fr));
  max-width: 1200px;
  margin: 0 auto;
}
.thumb { border: 0; background: transparent; padding: 0; cursor: pointer; display: grid; gap: 6px; }
.thumb img {
  width: 100%; height: auto; display: block; border-radius: 4px; background: #fff;
  box-shadow: 0 4px 14px rgba(0,0,0,.35); transition: transform .16s, box-shadow .16s;
  aspect-ratio: var(--aspect, .707); object-fit: cover; object-position: top;
}
.thumb:hover img { transform: translateY(-3px); box-shadow: 0 10px 22px rgba(0,0,0,.45); }
.thumb span { font-size: 11.5px; color: var(--muted); font-variant-numeric: tabular-nums; }
.thumb[aria-current='true'] img { outline: 2px solid var(--accent); outline-offset: 2px; }
.thumb[aria-current='true'] span { color: var(--accent); font-weight: 600; }

/* ------------------------------------------------------------ zoom */

.zoom {
  position: fixed;
  inset: 0;
  background: rgba(6, 8, 10, .96);
  z-index: 60;
  touch-action: none;
  overflow: hidden;
  cursor: zoom-out;
  opacity: 0;
  visibility: hidden;
  transition: opacity .26s ease, visibility 0s .26s;
}
.zoom[data-open='true'] {
  opacity: 1;
  visibility: visible;
  transition: opacity .26s ease;
}
.zoom.is-panning { cursor: grabbing; }

.zoom__canvas { position: absolute; top: 0; left: 0; transform-origin: 0 0; display: flex; }
.zoom__canvas.is-moving { will-change: transform; }
.zoom__page {
  position: relative;
  flex: none;
  background: #fff no-repeat center / 100% 100%;
  overflow: hidden;
}
.zoom__page img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}
/* Server-rendered detail for the region in view, laid exactly over the base. */
.zoom__hi { position: absolute; inset: auto; display: block; }
.zoom__close { position: fixed; top: 14px; right: 14px; z-index: 62; background: var(--chrome); }
.zoom__busy {
  position: fixed; bottom: 22px; right: 22px; z-index: 62;
  display: flex; align-items: center; gap: 8px;
  background: var(--chrome); color: var(--muted); font-size: 12.5px;
  padding: 7px 13px; border-radius: 999px; pointer-events: none;
}
.zoom__spin {
  width: 12px; height: 12px; border-radius: 50%;
  border: 2px solid var(--line); border-top-color: var(--accent);
  animation: spin .8s linear infinite;
}

.zoom__hint {
  position: fixed; bottom: 22px; left: 50%; transform: translateX(-50%);
  background: var(--chrome); color: var(--fg); font-size: 12.5px; padding: 8px 14px;
  border-radius: 999px; z-index: 62; pointer-events: none; transition: opacity .4s;
}

/* ----------------------------------------------------------- sheet */

.sheet-backdrop {
  position: fixed; inset: 0; background: rgba(0,0,0,.5); z-index: 50;
  display: none; align-items: flex-end; justify-content: center;
}
.sheet-backdrop[data-open='true'] { display: flex; }
@media (min-width: 720px) { .sheet-backdrop { align-items: center; } }

.sheet {
  width: min(440px, 100%);
  background: var(--panel);
  border-radius: 18px 18px 0 0;
  padding: 20px 20px calc(20px + env(safe-area-inset-bottom));
  box-shadow: var(--shadow);
  animation: sheet-in .22s cubic-bezier(.3,.9,.3,1);
}
@media (min-width: 720px) { .sheet { border-radius: 16px; } }
@keyframes sheet-in { from { transform: translateY(18px); opacity: 0; } }

.sheet h2 { margin: 0 0 4px; font-size: 16px; letter-spacing: -.01em; }
.sheet p { margin: 0 0 16px; font-size: 13px; color: var(--muted); }

.copyrow { display: flex; gap: 8px; margin-bottom: 14px; }
.copyrow input {
  flex: 1; min-width: 0; padding: 10px 12px; border-radius: 9px; font-size: 13px;
  border: 1px solid var(--line); background: color-mix(in srgb, var(--fg) 6%, transparent); color: var(--fg);
}

.share-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-bottom: 16px; }
.share-btn {
  display: grid; gap: 6px; place-items: center; padding: 12px 4px; border-radius: 12px;
  border: 1px solid var(--line); background: transparent; cursor: pointer; font-size: 11px; color: var(--muted);
}
.share-btn:hover { background: var(--hover); color: var(--fg); }
.share-btn svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.qr { display: grid; place-items: center; padding: 12px; background: #fff; border-radius: 12px; }
.qr img { width: 180px; height: 180px; display: block; }

/* ---------------------------------------------------------- toast */

.toast {
  position: fixed; left: 50%; bottom: calc(var(--bar-h) + 22px); transform: translate(-50%, 12px);
  background: var(--panel); color: var(--fg); border: 1px solid var(--line);
  padding: 10px 16px; border-radius: 999px; font-size: 13px; box-shadow: var(--shadow);
  opacity: 0; pointer-events: none; transition: opacity .2s, transform .2s; z-index: 70;
}
.toast[data-open='true'] { opacity: 1; transform: translate(-50%, 0); }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.loader {
  position: absolute; inset: 0; display: grid; place-items: center; z-index: 45;
  background: var(--bg); transition: opacity .3s; pointer-events: none;
}
.loader[hidden] { opacity: 0; }
.loader__spin {
  width: 30px; height: 30px; border-radius: 50%;
  border: 2.5px solid var(--line); border-top-color: var(--accent);
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* -------------------------------------------------------- responsive */

@media (max-width: 720px) {
  .brand__title { max-width: 42vw; font-size: 13px; }
  .bar__spacer { min-width: 4px; }
  .brand__sub { display: none; }
  .stage { padding: 8px; }
  .edge { display: none; }
  .panel { top: 0; width: 100%; }
  .thumbs { inset: 0; padding: 68px 14px 20px; }
  .thumbs__grid { grid-template-columns: repeat(auto-fill, minmax(86px, 1fr)); gap: 12px; }
}

@media (prefers-reduced-motion: reduce) {
  .bar, .panel, .book--sliding .pane, .toast { transition-duration: .01ms; }
  .turning { transition-duration: .01ms !important; }
}

body.is-embed .bar--top { --bar-h: 46px; }

/* Phone-width toolbars: a catalog with contents, search, share, fullscreen and
   an open-out link needs six buttons to fit beside the title, so they tighten
   up rather than the last one falling off the edge. */
@media (max-width: 480px) {
  .bar { gap: 2px; padding: 0 6px; }
  .pager { gap: 6px; }
  .pager__label { min-width: 58px; font-size: 12px; }
  .slider { min-width: 40px; }
  .bar .btn { width: 34px; height: 34px; }
  .bar .btn svg { width: 19px; height: 19px; }
  .brand { gap: 6px; padding-left: 2px; }
  .brand__title { max-width: 28vw; }
  .brand img { height: 20px; }
}

@media (max-width: 380px) {
  .bar .btn { width: 31px; height: 31px; }
  .brand__title { max-width: 22vw; }
}