:root {
  color-scheme: dark;
  --bg: #111111;
  --panel: rgba(20, 20, 20, 0.92);
  --line: rgba(255, 255, 255, 0.14);
  --text: #f2f2f2;
  --muted: #9f9f9f;
  --button-hover: rgba(255, 255, 255, 0.10);
  --page-size: min(calc((100vw - 80px) / 2), calc(100dvh - 138px), 900px);
}

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; overflow: hidden; }
body {
  background: radial-gradient(circle at 50% 44%, #292929 0%, #181818 38%, var(--bg) 78%);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  -webkit-font-smoothing: antialiased;
}
button, a { -webkit-tap-highlight-color: transparent; }
img { -webkit-user-drag: none; user-select: none; }

.viewer {
  width: 100%;
  height: 100dvh;
  min-height: 100%;
  display: grid;
  grid-template-rows: 62px minmax(0, 1fr) 30px;
}

.toolbar {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: max(10px, env(safe-area-inset-top)) max(18px, env(safe-area-inset-right)) 8px max(18px, env(safe-area-inset-left));
  background: linear-gradient(to bottom, rgba(8,8,8,.96), rgba(8,8,8,.78));
  border-bottom: 1px solid var(--line);
  z-index: 20;
}

.identity { min-width: 0; display: flex; align-items: baseline; gap: 13px; white-space: nowrap; }
.artist { font-size: 13px; font-weight: 600; letter-spacing: .11em; text-transform: uppercase; overflow: hidden; text-overflow: ellipsis; }
.portfolio-label { font-size: 12px; color: var(--muted); letter-spacing: .06em; }
.controls { display: flex; align-items: center; gap: 4px; flex: 0 0 auto; }
.icon-button {
  width: 38px; height: 38px; border: 0; border-radius: 50%; color: var(--text); background: transparent;
  display: inline-flex; align-items: center; justify-content: center; cursor: pointer; text-decoration: none;
  transition: background-color .2s ease, opacity .2s ease, transform .15s ease;
}
.icon-button:hover { background: var(--button-hover); }
.icon-button:active { transform: scale(.93); }
.icon-button:focus-visible { outline: 2px solid #fff; outline-offset: 2px; }
.icon-button:disabled { opacity: .28; cursor: default; }
.icon-button svg { width: 21px; height: 21px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.exit-fullscreen { display: none; }
:fullscreen .enter-fullscreen { display: none; }
:fullscreen .exit-fullscreen { display: block; }
.page-counter { min-width: 62px; text-align: center; color: #d7d7d7; font-size: 12px; font-variant-numeric: tabular-nums; letter-spacing: .04em; }
.separator { width: 1px; height: 22px; margin: 0 5px; background: var(--line); }

.stage {
  position: relative;
  min-width: 0;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px 24px 10px;
  overflow: hidden;
  touch-action: none;
}

#book {
  opacity: 0;
  visibility: hidden;
  transition: opacity .18s ease;
  filter: drop-shadow(0 22px 30px rgba(0,0,0,.48));
}
#book.visible { opacity: 1; visibility: visible; }
#book canvas { display: block; }

/* Portada independiente: evita cualquier página vacía a la izquierda. */
.cover-sequence {
  position: absolute;
  inset: 18px 24px 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  perspective: 2400px;
  z-index: 9;
  opacity: 1;
  visibility: visible;
  transition: opacity .16s ease, visibility .16s ease;
  --cover-shift: 0px;
  --cover-angle: 0deg;
  --spread-opacity: 0;
}
.cover-sequence.hidden { opacity: 0; visibility: hidden; pointer-events: none; }

.under-spread {
  position: absolute;
  left: 50%;
  top: 50%;
  width: calc(var(--page-size) * 2);
  height: var(--page-size);
  transform: translate(-50%, -50%);
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: #fff;
  opacity: var(--spread-opacity);
  box-shadow: 0 20px 34px rgba(0,0,0,.43);
  transition: opacity .08s linear;
  overflow: hidden;
}
.under-spread img { width: 100%; height: 100%; object-fit: contain; background: #fff; display: block; }

.cover-card {
  position: absolute;
  left: 50%;
  top: 50%;
  width: var(--page-size);
  height: var(--page-size);
  transform-origin: left center;
  transform: translate(-50%, -50%) translateX(var(--cover-shift)) rotateY(var(--cover-angle));
  transform-style: preserve-3d;
  cursor: grab;
  will-change: transform;
  filter: drop-shadow(0 22px 30px rgba(0,0,0,.52));
}
.cover-sequence.dragging .cover-card { cursor: grabbing; }
.cover-face {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: #fff;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}
.cover-face img { width: 100%; height: 100%; object-fit: contain; display: block; background: #fff; }
.cover-front { transform: translateZ(.5px); }
.cover-back { transform: rotateY(180deg) translateZ(.5px); }
.cover-back::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, rgba(0,0,0,.14), transparent 18%);
  pointer-events: none;
}
.cover-card::after {
  content: '';
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  box-shadow: inset 0 0 0 1px rgba(0,0,0,.10);
  pointer-events: none;
}

.loading {
  position: absolute;
  left: 50%;
  bottom: 22px;
  transform: translateX(-50%);
  display: flex;
  gap: 9px;
  align-items: center;
  justify-content: center;
  z-index: 14;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(8,8,8,.72);
  transition: opacity .3s ease, visibility .3s ease;
  pointer-events: none;
}
.loading.hidden { opacity: 0; visibility: hidden; }
.loading-mark { width: 18px; height: 18px; border-radius: 50%; border: 2px solid rgba(255,255,255,.16); border-top-color: rgba(255,255,255,.9); animation: spin .85s linear infinite; }
.loading-text { color: #c7c7c7; font-size: 10px; letter-spacing: .05em; text-transform: uppercase; }
.loading-error { max-width: min(90vw, 620px); text-align: center; line-height: 1.4; color: #fff; }
@keyframes spin { to { transform: rotate(360deg); } }

.gesture-hint {
  position: absolute;
  left: 50%;
  bottom: 20px;
  transform: translate(-50%, 10px);
  display: flex;
  align-items: center;
  gap: 10px;
  max-width: min(90vw, 470px);
  padding: 9px 14px;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 999px;
  background: rgba(8,8,8,.76);
  box-shadow: 0 8px 24px rgba(0,0,0,.3);
  color: #d3d3d3;
  font-size: 12px;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  z-index: 12;
  transition: opacity .35s ease, transform .35s ease, visibility .35s ease;
}
.gesture-hint.visible { opacity: 1; visibility: visible; transform: translate(-50%, 0); }
.gesture-hint svg { width: 25px; height: 25px; flex: 0 0 auto; fill: none; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; }
.footer-note { display: flex; align-items: center; justify-content: center; padding-bottom: max(7px, env(safe-area-inset-bottom)); color: #777; font-size: 10px; letter-spacing: .035em; }

@media (max-width: 720px) {
  :root { --page-size: min(calc(100vw - 20px), calc(100dvh - 96px), 900px); }
  .viewer { grid-template-rows: 54px minmax(0, 1fr) 24px; }
  .toolbar { padding-left: 10px; padding-right: 10px; gap: 8px; }
  .identity { gap: 0; }
  .artist { max-width: 155px; font-size: 10px; letter-spacing: .08em; }
  .portfolio-label { display: none; }
  .controls { gap: 0; }
  .icon-button { width: 34px; height: 34px; }
  .icon-button svg { width: 19px; height: 19px; }
  .page-counter { min-width: 52px; font-size: 11px; }
  .separator { margin: 0 2px; }
  .stage { padding: 10px 8px 4px; }
  .cover-sequence { inset: 10px 8px 4px; }
  .under-spread { width: var(--page-size); grid-template-columns: 1fr; }
  .under-spread .under-left { display: none; }
  .footer-note { font-size: 9px; }
  .gesture-hint { bottom: 12px; width: max-content; max-width: calc(100vw - 24px); font-size: 11px; }
  .loading { bottom: 12px; }
}

@media (max-height: 520px) {
  :root { --page-size: min(calc((100vw - 50px) / 2), calc(100dvh - 58px)); }
  .viewer { grid-template-rows: 48px minmax(0, 1fr); }
  .footer-note { display: none; }
  .toolbar { padding-top: 5px; padding-bottom: 5px; }
  .stage { padding: 6px 12px; }
  .cover-sequence { inset: 6px 12px; }
  .gesture-hint { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}

/* Contraportada independiente. El motor dibuja la última hoja en la mitad
   izquierda de un lienzo doble; aquí recortamos esa mitad y la centramos. */
@media (min-width: 721px) and (min-height: 521px) {
  #book.last-page-centered {
    width: var(--page-size) !important;
    max-width: var(--page-size) !important;
    min-width: 0 !important;
    overflow: hidden;
  }
  #book.last-page-centered .stf__wrapper {
    width: 100% !important;
    padding-bottom: 100% !important;
    overflow: hidden;
  }
  #book.last-page-centered .stf__canvas {
    width: 200% !important;
    max-width: none !important;
    height: 100% !important;
    transform: translateX(0);
  }
}


/* Versión tablet + zoom --------------------------------------------------- */
html.flipbook-single-page {
  --page-size: min(calc(100vw - 88px), calc(100dvh - 126px), 900px);
}
html.flipbook-single-page .under-spread {
  width: var(--page-size);
  grid-template-columns: 1fr;
}
html.flipbook-single-page .under-spread .under-left { display: none; }

.page-arrow {
  position: absolute;
  top: 50%;
  width: 54px;
  height: 54px;
  margin: 0;
  padding: 0;
  border: 1px solid rgba(255,255,255,.18);
  border-radius: 50%;
  background: rgba(8,8,8,.72);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transform: translateY(-50%);
  z-index: 18;
  cursor: pointer;
  box-shadow: 0 8px 24px rgba(0,0,0,.35);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  transition: opacity .2s ease, background-color .2s ease, transform .15s ease;
}
.page-arrow-prev { left: max(10px, env(safe-area-inset-left)); }
.page-arrow-next { right: max(10px, env(safe-area-inset-right)); }
.page-arrow:hover { background: rgba(25,25,25,.92); }
.page-arrow:active { transform: translateY(-50%) scale(.92); }
.page-arrow:focus-visible { outline: 2px solid #fff; outline-offset: 3px; }
.page-arrow:disabled { opacity: .18; cursor: default; }
.page-arrow svg { width: 27px; height: 27px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }

.zoom-viewer {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: grid;
  grid-template-rows: 58px minmax(0, 1fr) 34px;
  background: rgba(6,6,6,.97);
  color: #fff;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity .18s ease, visibility .18s ease;
}
.zoom-viewer.open { opacity: 1; visibility: visible; pointer-events: auto; }
.zoom-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: max(8px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) 8px max(16px, env(safe-area-inset-left));
  border-bottom: 1px solid rgba(255,255,255,.14);
  background: rgba(10,10,10,.96);
}
.zoom-page-label { font-size: 12px; letter-spacing: .06em; color: #d0d0d0; }
.zoom-controls { display: flex; align-items: center; gap: 6px; }
.zoom-control, .zoom-percent, .zoom-close {
  min-width: 40px;
  height: 40px;
  padding: 0 10px;
  border: 0;
  border-radius: 20px;
  background: rgba(255,255,255,.09);
  color: #fff;
  font: inherit;
  cursor: pointer;
}
.zoom-control { font-size: 24px; line-height: 1; }
.zoom-percent { min-width: 70px; font-size: 12px; font-variant-numeric: tabular-nums; }
.zoom-close { margin-left: 6px; font-size: 29px; line-height: 1; }
.zoom-control:hover, .zoom-percent:hover, .zoom-close:hover { background: rgba(255,255,255,.16); }
.zoom-control:disabled { opacity: .3; cursor: default; }
.zoom-canvas {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 14px;
  touch-action: none;
  cursor: zoom-in;
}
.zoom-canvas.pannable { cursor: grab; }
.zoom-canvas.dragging { cursor: grabbing; }
.zoom-canvas img {
  display: block;
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  transform-origin: center center;
  will-change: transform;
  user-select: none;
  box-shadow: 0 18px 50px rgba(0,0,0,.55);
}
.zoom-help {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 12px max(7px, env(safe-area-inset-bottom));
  color: #8f8f8f;
  font-size: 10px;
  letter-spacing: .025em;
  text-align: center;
}

@media (max-width: 720px) {
  html.flipbook-single-page { --page-size: min(calc(100vw - 20px), calc(100dvh - 90px), 900px); }
  .page-arrow { width: 43px; height: 43px; }
  .page-arrow-prev { left: max(5px, env(safe-area-inset-left)); }
  .page-arrow-next { right: max(5px, env(safe-area-inset-right)); }
  .page-arrow svg { width: 23px; height: 23px; }
  .zoom-viewer { grid-template-rows: 54px minmax(0, 1fr) 28px; }
  .zoom-page-label { display: none; }
  .zoom-toolbar { justify-content: flex-end; padding-left: 8px; padding-right: 8px; }
  .zoom-control, .zoom-percent, .zoom-close { min-width: 38px; height: 38px; }
  .zoom-percent { min-width: 64px; }
  .zoom-canvas { padding: 8px; }
  .zoom-help { font-size: 9px; }
}

/* En tablet, el lienzo del motor adopta el tamaño real de una sola hoja.
   Así no se recorta al girar el dispositivo a horizontal. */
html.flipbook-single-page #book {
  width: var(--page-size) !important;
  max-width: var(--page-size) !important;
  min-width: 0 !important;
}