:root {
  --book-bg: #f5f7fb;
  --book-panel: #ffffff;
  --book-ink: #0f172a;
  --book-muted: #5b6b81;
  --book-accent: #6366f1;
  --book-outline: #d6deeb;
  --book-shadow: 0 18px 42px rgba(15, 23, 42, 0.16);
  --book-wrap-max: min(1280px, 100%);
  --book-spread-width: 100%;
  --book-spread-height: min(720px, 82vh);
  --viewer-btn-size: 2.75rem;
}

.book-inline {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: var(--book-wrap-max);
  width: 100%;
  margin: 0 auto;
}

.book-inline[data-book-images="hidden"] .book img,
.book-inline[data-book-images="hidden"] .book picture,
.book-inline[data-book-images="hidden"] .book figure,
.book-inline[data-book-images="hidden"] .book .image-box {
  display: none !important;
}

.book-inline[data-book-images="hidden"] .thumbs {
  display: none;
}

.book-layout {
  display: grid;
  grid-template-columns: minmax(0, 42%) minmax(0, 42%) minmax(140px, 15%);
  gap: 12px;
  align-items: stretch;
}

.viewer-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: nowrap;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.98), rgba(238, 242, 255, 0.9));
  border: 1px solid var(--book-outline);
  border-radius: 14px;
  padding: 10px 14px;
  box-shadow: 0 10px 26px rgba(15, 23, 42, 0.08);
}

.book-toolbar {
  margin: 0;
}

.viewer-bar h1 {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--book-ink);
  flex: 1 1 auto;
  min-width: 0;
  text-align: center;
}

.viewer-bar .controls {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  position: relative;
}

.viewer-bar .controls-inner {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.viewer-bar .controls .goto {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.viewer-bar .controls input[type="number"] {
  width: calc(2.35rem * 0.77);
  height: calc(2.35rem * 0.77);
  padding: 0.2rem 0.3rem;
  border-radius: 0.7rem;
  border: 1px solid var(--book-outline);
  background: #fff;
  color: var(--book-ink);
  font-size: 0.95rem;
  text-align: center;
}

.viewer-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  border-radius: 0.7rem;
  border: 0;
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.26);
  background: #ffffff;
  color: var(--book-accent);
  font-weight: 600;
  font-size: 1.15rem;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, transform 0.12s ease, box-shadow 0.15s ease;
  -webkit-appearance: none;
  appearance: none;
  font-family: inherit;
  line-height: 1;
}

.viewer-btn--menu {
  display: none;
}


.viewer-btn:visited,
.viewer-btn--back:visited,
.viewer-btn--link:visited {
  color: var(--book-accent);
}

.viewer-btn--back,
.viewer-btn--link,
.viewer-btn--tts {
  color: var(--book-accent);
}

.viewer-btn--overlay {
  position: relative;
}

.viewer-btn--overlay::after {
  content: attr(data-icon-overlay);
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1em;
  line-height: 1;
  opacity: 0;
  pointer-events: none;
}

.viewer-btn--overlay[data-overlay-state="off"]::after {
  opacity: 1;
}

.viewer-btn--cnpy {
  font-size: 1.05rem;
  letter-spacing: 0.06em;
}

.viewer-btn--combo {
  font-size: 1.05rem;
  letter-spacing: 0.04em;
}

.viewer-btn--active {
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.45);
  background: rgba(99, 102, 241, 0.18);
  color: var(--book-accent);
}

.viewer-btn--pill,
.viewer-btn--mode {
  width: auto;
  min-width: 2.75rem;
  padding: 0.45rem 1rem;
}

.viewer-btn--pill {
  border-radius: 999px;
}

.viewer-btn--mode {
  border-radius: 999px;
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.35);
  background: rgba(148, 163, 184, 0.12);
  color: var(--book-ink);
  font-size: 0.92rem;
}

.viewer-btn--mode.active {
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.45);
  background: rgba(99, 102, 241, 0.18);
  color: var(--book-accent);
}

.viewer-btn:hover,
.viewer-btn:focus {
  background: rgba(99, 102, 241, 0.14);
  box-shadow: 0 12px 30px rgba(99, 102, 241, 0.22);
  transform: translateY(-1px);
  text-decoration: none;
  color: var(--book-accent);
}

.viewer-btn[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.3);
  background: rgba(148, 163, 184, 0.12);
  color: var(--book-muted);
}

.viewer-bar .controls-inner .viewer-select--lang {
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  min-width: var(--viewer-btn-size);
  padding: 0 1.3rem 0 0.45rem;
  border-radius: 0.7rem;
  border: 0;
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.26);
  background-color: #ffffff;
  color: var(--book-accent);
  font-weight: 700;
  font-size: 0.74rem;
  letter-spacing: 0.03em;
  text-align: center;
  text-align-last: center;
  cursor: pointer;
  -webkit-appearance: none;
  appearance: none;
  background-image:
    linear-gradient(45deg, transparent 50%, currentColor 50%),
    linear-gradient(135deg, currentColor 50%, transparent 50%);
  background-position:
    calc(100% - 12px) calc(50% - 3px),
    calc(100% - 7px) calc(50% - 3px);
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  transition: background-color 0.15s ease, transform 0.12s ease, box-shadow 0.15s ease;
}

.viewer-bar .controls-inner .viewer-select--lang:hover,
.viewer-bar .controls-inner .viewer-select--lang:focus {
  background-color: rgba(99, 102, 241, 0.14);
  box-shadow: 0 12px 30px rgba(99, 102, 241, 0.22);
  transform: translateY(-1px);
  outline: none;
}

.viewer-bar .controls-inner .viewer-select--lang:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.3);
  background-color: rgba(148, 163, 184, 0.12);
  color: var(--book-muted);
}

.book-combined {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.book-combined-block {
  border-radius: 0.75rem;
  padding: 0.55rem 0.75rem;
  background: rgba(148, 163, 184, 0.12);
  transition: background 0.15s ease;
}

.book-combined-block--secondary {
  background: rgba(99, 102, 241, 0.1);
}

.book-combined-block :where(p, h1, h2, h3, h4, h5, h6) {
  margin-top: 0.35rem;
  margin-bottom: 0.35rem;
}

.book-combined-block :where(p:first-child, h1:first-child, h2:first-child, h3:first-child,
  h4:first-child, h5:first-child, h6:first-child) {
  margin-top: 0;
}

.book-combined-block :where(p:last-child, h1:last-child, h2:last-child, h3:last-child,
  h4:last-child, h5:last-child, h6:last-child) {
  margin-bottom: 0;
}

.viewer-btn--muted {
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.35);
  background: rgba(148, 163, 184, 0.14);
  color: var(--book-muted);
}

.viewer-btn--muted:hover,
.viewer-btn--muted:focus {
  background: rgba(148, 163, 184, 0.24);
  box-shadow: 0 10px 24px rgba(148, 163, 184, 0.24);
  color: var(--book-ink);
}

.viewer-btn.is-copied {
  box-shadow: inset 0 0 0 1px rgba(34, 197, 94, 0.38);
  background: rgba(34, 197, 94, 0.18);
  color: #15803d;
}

.page-label {
  font-weight: 600;
  color: var(--book-muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  text-align: center;
  border: 1px solid var(--book-outline);
  border-radius: 0.7rem;
  background: #fff;
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.16);
}


.book-stage {
  grid-column: 1 / span 2;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 12px;
  background: var(--book-panel);
  border-radius: 16px;
  border: 1px solid var(--book-outline);
  padding: 0;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.12);
  min-height: var(--book-spread-height);
}

.book {
  position: relative;
  flex: 1 1 auto;
  width: var(--book-spread-width);
  max-width: 100%;
  height: var(--book-spread-height);
  margin: 0 auto;
  perspective: 2000px;
  transform-style: preserve-3d;
}

.spread {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-radius: 16px;
  overflow: hidden;
  background: var(--book-panel);
  box-shadow: 0 26px 44px rgba(15, 23, 42, 0.16);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s ease;
}

.spread.active {
  opacity: 1;
  pointer-events: auto;
}

.page {
  position: relative;
  background: var(--book-panel);
  color: var(--book-ink);
  display: flex;
  align-items: stretch;
  justify-content: stretch;
  overflow: hidden;
  cursor: pointer;
}

.page.left {
  border-right: 1px solid rgba(226, 232, 240, 0.8);
}

.page.right {
  border-left: 1px solid rgba(226, 232, 240, 0.8);
  background: #f8fafc;
}

.page-inner {
  padding: 28px;
  width: 100%;
  overflow: auto;
}

.kokoro-content {
  font-size: clamp(0.95rem, 0.9rem + 0.25vw, 1.05rem);
  line-height: 1.7;
  color: var(--book-ink);
}

.kokoro-content h1,
.kokoro-content h2,
.kokoro-content h3 {
  margin: 0.35rem 0 0.6rem;
}

.kokoro-content p {
  margin: 0.85rem 0;
}

.kokoro-content img,
.kokoro-content video,
.kokoro-content audio {
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  box-shadow: 0 12px 26px rgba(15, 23, 42, 0.18);
}

.kokoro-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0 18px;
  font-size: 0.95rem;
  background: rgba(255, 255, 255, 0.98);
  border-radius: 12px;
  overflow: hidden;
}

.kokoro-content th,
.kokoro-content td {
  border: 1px solid rgba(148, 163, 184, 0.4);
  padding: 10px 12px;
  text-align: left;
  vertical-align: middle;
}

.kokoro-content th {
  background: rgba(99, 102, 241, 0.12);
  font-weight: 700;
  color: var(--book-ink);
}

.kokoro-content tbody tr:nth-child(even) {
  background: rgba(99, 102, 241, 0.06);
}

.image-box {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #eef2ff, #f8fafc);
}

.image-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-box.placeholder {
  font-size: 0.95rem;
  color: var(--book-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.page-turn {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(90deg, rgba(15, 23, 42, 0.08), rgba(15, 23, 42, 0));
  opacity: 0;
}

.spread.turn-next .page-turn,
.spread.turn-prev .page-turn {
  animation-duration: 900ms;
  animation-timing-function: ease-in-out;
  animation-fill-mode: both;
}

.spread.turn-next .page-turn {
  animation-name: flipNext;
}

.spread.turn-prev .page-turn {
  animation-name: flipPrev;
}

@keyframes flipNext {
  0% { opacity: 0; transform: rotateY(0deg); }
  20% { opacity: 0.6; }
  100% { opacity: 0; transform: rotateY(-180deg); }
}

@keyframes flipPrev {
  0% { opacity: 0; transform: rotateY(-180deg); }
  20% { opacity: 0.6; }
  100% { opacity: 0; transform: rotateY(0deg); }
}

.drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: min(360px, 92vw);
  height: 100vh;
  background: var(--book-panel);
  border-left: 1px solid var(--book-outline);
  box-shadow: -24px 0 48px rgba(15, 23, 42, 0.18);
  transform: translateX(110%);
  transition: transform 0.25s ease;
  z-index: 60;
  display: flex;
  flex-direction: column;
}

.drawer.open {
  transform: translateX(0);
}

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-bottom: 1px solid var(--book-outline);
  gap: 10px;
  flex-wrap: wrap;
}

.drawer-header .tabs {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex: 1 1 auto;
}

.drawer-header .tab,
.drawer-header .close {
  border: 1px solid rgba(148, 163, 184, 0.45);
  background: rgba(244, 247, 255, 0.9);
  border-radius: 10px;
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  min-width: var(--viewer-btn-size);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.05rem;
  padding: 0;
}

.drawer-header .goto {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: 6px;
}

.drawer-header .goto input[type="number"] {
  width: calc(var(--viewer-btn-size) * 0.77);
  height: calc(var(--viewer-btn-size) * 0.77);
  padding: 0.2rem 0.3rem;
  border-radius: 0.7rem;
  border: 1px solid var(--book-outline);
  background: #fff;
  color: var(--book-ink);
  font-weight: 700;
  text-align: center;
  font-size: 1rem;
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.18);
}

.drawer-header .viewer-btn.viewer-btn--go {
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  min-width: var(--viewer-btn-size);
  font-size: 1rem;
}

.drawer-body {
  padding: 12px;
  overflow: auto;
  flex: 1;
}

.drawer-panel.hidden {
  display: none;
}

.drawer .toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.drawer .toc a {
  text-decoration: none;
  font-weight: 600;
  color: var(--book-ink);
  display: block;
  padding: 0.45rem 0.6rem;
  border-radius: 10px;
  border: 1px solid rgba(148, 163, 184, 0.4);
  background: rgba(248, 250, 255, 0.9);
}

.drawer .toc a:hover {
  background: rgba(99, 102, 241, 0.12);
  border-color: rgba(99, 102, 241, 0.4);
}

.drawer .thumbs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.drawer .thumb {
  display: block;
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: #f8fafc;
  text-decoration: none;
  color: inherit;
}

.drawer .thumb img {
  width: 100%;
  height: 110px;
  object-fit: contain;
  display: block;
}

.drawer .thumb span {
  position: absolute;
  right: 8px;
  bottom: 8px;
  background: rgba(15, 23, 42, 0.75);
  color: #fff;
  font-size: 0.8rem;
  padding: 2px 6px;
  border-radius: 999px;
}

.drawer .thumb.current {
  outline: 2px solid var(--book-accent);
}

.drawer .thumb.thumb--empty {
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  background: repeating-linear-gradient(-45deg, #f1f5f9, #f1f5f9 10px, #e2e8f0 10px, #e2e8f0 20px);
}


.book-list {
  grid-column: 3 / 4;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  background: var(--book-panel);
  border-radius: 16px;
  border: 1px solid var(--book-outline);
  padding: 0;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.1);
  overflow: auto;
  max-height: var(--book-spread-height);
  min-height: var(--book-spread-height);
}

.book-list .vgroup {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  border-radius: 12px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(248, 250, 255, 0.85);
  padding: 0.35rem 0.4rem;
}

.book-list .vgroup + .vgroup {
  margin-top: 0.15rem;
}

.book-list .vgroup-title {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0.45rem;
  border-radius: 10px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--book-ink);
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  text-align: left;
}

.book-list .vgroup-title:hover,
.book-list .vgroup-title:focus {
  border-color: rgba(99, 102, 241, 0.35);
  background: rgba(99, 102, 241, 0.08);
}

.book-list .vgroup-caret {
  display: inline-block;
  transition: transform 0.18s ease;
  font-size: 0.95rem;
}

.book-list .vgroup[aria-expanded="true"] .vgroup-caret {
  transform: rotate(90deg);
}

.book-list .vgroup[aria-expanded="false"] .vgroup-caret {
  transform: rotate(0deg);
}

.book-list .vgroup-count {
  color: var(--book-muted);
  font-weight: 600;
  font-size: 0.85rem;
}

.book-list .vgroup-body {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  padding-top: 0.25rem;
}

.book-list .vgroup[aria-expanded="false"] .vgroup-body {
  display: none;
}

.book-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 0.65rem;
  border-radius: 12px;
  border: 1px solid rgba(148, 163, 184, 0.45);
  background: linear-gradient(135deg, rgba(248, 250, 255, 0.95), rgba(255, 255, 255, 0.98));
  text-decoration: none;
  color: var(--book-ink);
  font-weight: 600;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.book-item:hover,
.book-item:focus {
  transform: translateY(-2px);
  border-color: rgba(99, 102, 241, 0.4);
  box-shadow: 0 12px 26px rgba(99, 102, 241, 0.22);
}

.book-item.active {
  outline: 2px solid var(--book-accent);
  box-shadow: 0 14px 30px rgba(99, 102, 241, 0.28);
}

.book-item__icon {
  font-size: 1.2rem;
}

.book-list__empty {
  margin: 0;
  padding: 0.75rem;
  border-radius: 12px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(248, 250, 255, 0.9);
  text-align: center;
  color: var(--book-muted);
}

.book-wrap--tts-hidden [data-role="read"] {
  display: none !important;
}

.tap-zone {
  position: absolute;
  left: 0;
  right: 0;
  height: 50%;
  z-index: 5;
}

.tap-zone.top { top: 0; }
.tap-zone.bottom { bottom: 0; }

.book-error {
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.95), rgba(226, 232, 240, 0.88));
  border-radius: 20px;
  padding: 32px;
  text-align: center;
  color: var(--book-ink);
  box-shadow: var(--book-shadow);
}

.book-error__panel {
  max-width: 520px;
  margin: 0 auto;
  background: var(--book-panel);
  border-radius: 16px;
  padding: 24px;
  border: 1px solid var(--book-outline);
}

.book-error__path {
  margin-top: 12px;
  color: var(--book-muted);
  font-family: 'SFMono-Regular', Menlo, Consolas, monospace;
}

@media (max-width: 1024px) {
  :root {
    --book-spread-height: min(620px, 78vh);
  }

  .book-layout {
    grid-template-columns: 1fr;
  }

  .book-stage {
    grid-column: 1;
  }

  .book-list {
    grid-column: 1;
    margin-top: 16px;
    box-shadow: none;
    background: transparent;
    padding: 0;
    min-height: auto;
  }

  .viewer-bar {
    flex-wrap: wrap;
  }
}

@media (max-width: 900px) {
  :root {
    --book-spread-width: 100vw;
    --book-spread-height: calc(100dvh - 140px);
  }

  .viewer-bar {
    position: sticky;
    top: 0;
    z-index: 40;
    gap: 8px;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(6px);
    align-items: center;
    flex-wrap: wrap;
  }

  .viewer-bar h1 {
    order: 1;
    flex: 1 1 auto;
    text-align: left;
    font-size: 1rem;
  }

  .viewer-bar .controls {
    order: 1;
    flex: 0 0 auto;
  }

  .book {
    width: 100%;
    height: var(--book-spread-height);
  }

  .spread {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: 1fr;
    align-content: stretch;
  }

  .page.left {
    border-right: none;
  }

  .page.right {
    border-left: none;
  }

  .page-inner {
    padding: 18px;
  }

  .page {
    height: 100%;
    min-height: 0;
    cursor: default;
    grid-column: 1;
    grid-row: 1;
  }

  .page.right {
    position: relative;
    z-index: 1;
  }

  .page.left {
    position: relative;
    z-index: 2;
    background: rgba(255, 255, 255, 0.7);
  }

  .image-box {
    min-height: 42vh;
  }

  .drawer {
    width: 100vw;
    height: 100dvh;
  }

  .drawer .thumb img {
    height: 24vh;
    max-height: 160px;
  }
}

@media (max-width: 720px) {
  .viewer-bar {
    flex-wrap: nowrap;
    align-items: center;
  }

  .viewer-bar h1 {
    order: 1;
    flex: 1 1 auto;
    text-align: left;
    margin: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .viewer-bar .controls {
    order: 2;
    justify-content: flex-end;
    flex: 0 0 auto;
    margin-left: auto;
  }

  .viewer-btn--menu {
    display: inline-flex;
  }

  .viewer-bar .controls-inner {
    display: none;
    position: absolute;
    left: 50%;
    right: auto;
    top: calc(100% + 10px);
    transform: translateX(-50%);
    gap: 10px;
    padding: 12px;
    border-radius: 14px;
    border: 1px solid rgba(148, 163, 184, 0.35);
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 22px 48px rgba(15, 23, 42, 0.22);
    width: min(420px, 94vw);
    min-width: min(320px, 94vw);
    max-height: min(75vh, 420px);
    overflow-x: visible;
    overflow-y: auto;
    z-index: 50;
  }

  .viewer-bar .controls[data-menu-open="true"] .controls-inner {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, auto));
    justify-items: center;
    align-items: center;
  }

  .viewer-bar .controls-inner > .viewer-btn {
    width: var(--viewer-btn-size);
    justify-self: center;
  }

  .viewer-bar .controls-inner > a.viewer-btn {
    width: var(--viewer-btn-size);
    min-width: var(--viewer-btn-size);
    justify-self: center;
  }

  .viewer-bar .controls-inner > .viewer-btn.viewer-btn--pill,
  .viewer-bar .controls-inner > .viewer-btn.viewer-btn--mode,
  .viewer-bar .controls-inner > .viewer-btn.viewer-btn--go {
    width: auto;
    min-width: var(--viewer-btn-size);
  }

  .viewer-bar .controls-inner > .page-label {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    width: var(--viewer-btn-size);
    height: var(--viewer-btn-size);
  }

  .viewer-bar .controls-inner .goto {
    grid-column: span 3;
    width: 100%;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 8px;
    align-items: center;
  }

  .viewer-bar .controls-inner .goto input[type="number"] {
    width: var(--viewer-btn-size);
  }

  .viewer-bar .controls-inner select,
  .viewer-bar .controls-inner .viewer-select {
    grid-column: span 3;
    width: 100%;
  }

  .viewer-bar .controls-inner .viewer-select--lang {
    grid-column: auto;
    width: var(--viewer-btn-size);
    min-width: var(--viewer-btn-size);
    text-align: center;
    text-align-last: center;
    padding: 0 1.3rem 0 0.45rem;
    font-size: 0.74rem;
    letter-spacing: 0.03em;
    background-position:
      calc(100% - 12px) calc(50% - 3px),
      calc(100% - 7px) calc(50% - 3px);
  }

  .viewer-bar .controls-inner .viewer-btn.viewer-btn--go {
    width: var(--viewer-btn-size);
  }

}

@media (max-width: 560px) {
  :root {
    --book-spread-height: calc(100dvh - 150px);
  }

  .viewer-bar h1 {
    font-size: 0.95rem;
  }

  .viewer-bar .controls input[type="number"] {
    width: 52px;
  }

  .book-stage {
    padding: 10px;
  }
}

.shareqr-print-stamp {
  display: none;
}

.tts-settings {
  position: relative;
  display: inline-flex;
  align-items: center;
}

.tts-settings > [data-tts-settings-toggle] {
  width: var(--viewer-btn-size);
  height: var(--viewer-btn-size);
  min-width: var(--viewer-btn-size);
  max-width: var(--viewer-btn-size);
  flex: 0 0 var(--viewer-btn-size);
}

.tts-settings__panel {
  position: absolute;
  top: calc(100% + 12px);
  left: 50%;
  right: auto;
  width: min(320px, calc(100vw - 1.5rem));
  min-width: 240px;
  display: none;
  gap: 0.9rem;
  padding: 1rem;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(255, 255, 255, 0.99);
  box-shadow: 0 18px 44px rgba(15, 23, 42, 0.18);
  z-index: 65;
  opacity: 0;
  transform: translate(-50%, -6px);
  pointer-events: none;
  transition: opacity 0.18s ease, transform 0.18s ease;
}

.tts-settings__panel.is-open {
  display: grid;
  opacity: 1;
  transform: translate(-50%, 0);
  pointer-events: auto;
}

.tts-settings__field {
  display: grid;
  gap: 0.35rem;
  font-size: 0.84rem;
  color: var(--book-ink);
}

.tts-settings__field > span {
  font-weight: 600;
}

.tts-settings__range {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.6rem;
  align-items: center;
}

.tts-settings__range output {
  min-width: 2.5rem;
  text-align: right;
  color: var(--book-muted);
}

.tts-settings__field--chunk-size .tts-settings__range {
  grid-template-columns: 0.95rem minmax(0, 1fr) auto;
  gap: 0.35rem;
  align-items: center;
}

.tts-settings__field--chunk-size input[type="checkbox"] {
  margin: 0;
  padding: 0;
  inline-size: 0.95rem;
  block-size: 0.95rem;
}

.tts-settings__field--chunk-size output {
  margin: 0;
  padding: 0;
  min-width: 2rem;
  line-height: 1;
}

@media (max-width: 720px) {
  .viewer-bar .controls[data-menu-open="true"] .controls-inner {
    overflow: visible;
  }

  .viewer-bar .controls-inner .tts-settings {
    grid-column: span 1;
    width: auto;
    justify-content: center;
  }

  .viewer-bar .controls-inner .tts-settings > .viewer-btn,
  .viewer-bar .controls-inner .tts-settings > [data-tts-settings-toggle] {
    width: var(--viewer-btn-size);
    min-width: var(--viewer-btn-size);
    max-width: var(--viewer-btn-size);
  }

  .viewer-bar .controls-inner .tts-settings__panel {
    position: absolute;
    top: calc(100% + 12px);
    left: 50%;
    right: auto;
    width: min(300px, calc(100vw - 1rem));
    min-width: min(220px, calc(100vw - 1rem));
    z-index: 120;
  }
}

.viewer-btn--save {
  width: 44px;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  font-size: 1.1rem;
}

.tts-settings__save {
  justify-self: end;
  justify-content: center;
}

.tts-settings__field .viewer-select,
.tts-settings__field input[type="range"] {
  width: 100%;
}

.tts-settings__field .viewer-select {
  min-height: 56px;
  padding: 0.85rem 1.15rem;
  font-size: 1.05rem;
  border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: #fff;
  box-shadow: inset 0 0 0 1px rgba(226, 232, 240, 0.75);
}

.tts-settings__field input[type="range"] {
  min-height: 40px;
}

@media (max-width: 720px) {
  .viewer-bar .controls-inner .tts-settings__panel {
    padding: 1rem;
    gap: 1rem;
    border-radius: 14px;
  }

  .tts-settings__field {
    font-size: 0.95rem;
  }

  .tts-settings__field .viewer-select {
    min-height: 58px;
    font-size: 1.05rem;
  }
}

.tts-settings__field input[type="checkbox"] {
  inline-size: 1.1rem;
  block-size: 1.1rem;
}

.tts-settings__field--chunk-size input[type="checkbox"] {
  inline-size: 0.95rem;
  block-size: 0.95rem;
}