:root {
  --canvas: oklch(17.5% 0.009 70);
  --canvas-deep: oklch(12.8% 0.007 68);
  --surface: oklch(15.2% 0.008 68);
  --paper: oklch(97.2% 0.009 83);
  --page-ink: oklch(31% 0.016 67);
  --ink: oklch(91% 0.012 78);
  --ink-soft: oklch(69% 0.014 75);
  --line: oklch(82% 0.012 78 / 0.12);
  --line-strong: oklch(87% 0.014 78 / 0.28);
  --accent: oklch(59% 0.09 35);
  --accent-dark: oklch(66% 0.085 38);
  --danger: oklch(70% 0.12 28);
  --focus: oklch(76% 0.095 42);
  --control-surface: oklch(14.2% 0.007 68);
  --track: oklch(80% 0.014 75 / 0.2);
  --shadow-ambient: oklch(2% 0.002 70 / 0.58);
  --shadow-deep: oklch(2% 0.002 70 / 0.72);
  --font-display: Baskerville, "Iowan Old Style", "Songti SC", "STSong", serif;
  --font-ui: "Avenir Next", "PingFang SC", "Microsoft YaHei", sans-serif;
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  min-width: 18rem;
  color-scheme: dark;
  background: var(--canvas-deep);
}

body {
  min-width: 18rem;
  min-height: 100svh;
  height: 100dvh;
  margin: 0;
  overflow: hidden;
  color: var(--ink);
  background:
    radial-gradient(ellipse 74% 66% at 50% 48%, oklch(31% 0.012 72 / 0.36), transparent 69%),
    linear-gradient(180deg, oklch(20% 0.009 70), var(--canvas-deep));
  font-family: var(--font-ui);
  font-size: 1rem;
  -webkit-font-smoothing: antialiased;
}

body::before {
  position: fixed;
  z-index: 0;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.92' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.34'/%3E%3C/svg%3E");
  content: "";
  opacity: 0.032;
  pointer-events: none;
  mix-blend-mode: soft-light;
}

button,
a,
input {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
}

button:focus-visible,
a:focus-visible,
input:focus-visible,
.reader-main:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.75rem 1rem;
  color: var(--canvas-deep);
  background: var(--ink);
  transform: translateY(-160%);
  transition: transform 180ms var(--ease-out-quart);
}

.skip-link:focus {
  transform: translateY(0);
}

.app-shell {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100dvh;
  min-height: 100svh;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  overflow: hidden;
  isolation: isolate;
}

.masthead {
  position: relative;
  z-index: 10;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: center;
  gap: 2rem;
  min-height: clamp(5.25rem, 9.5vh, 6.5rem);
  padding:
    max(1rem, env(safe-area-inset-top))
    max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-right))
    1rem
    max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-left));
}

.masthead::after {
  position: absolute;
  right: max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-right));
  bottom: 0;
  left: max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-left));
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line) 12%, var(--line) 88%, transparent);
  content: "";
}

.book-identity {
  display: inline-flex;
  align-items: center;
  gap: 1.15rem;
  min-width: 0;
}

.book-mark {
  position: relative;
  display: grid;
  width: 3rem;
  height: 3.2rem;
  flex: 0 0 auto;
  place-items: center;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 400;
  line-height: 1;
}

.book-mark::before {
  position: absolute;
  top: 0.2rem;
  right: -0.5rem;
  bottom: 0.2rem;
  width: 1px;
  background: var(--line-strong);
  content: "";
}

.book-mark::after {
  position: absolute;
  right: -0.82rem;
  bottom: 0.1rem;
  width: 0.45rem;
  height: 0.45rem;
  background: var(--accent);
  content: "";
}

.book-meta {
  display: grid;
  gap: 0.08rem;
  min-width: 0;
}

.book-title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 400;
  letter-spacing: 0.18em;
  white-space: nowrap;
}

.book-subtitle {
  overflow: hidden;
  color: var(--ink-soft);
  font-family: var(--font-display);
  font-size: 0.64rem;
  letter-spacing: 0.2em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.reading-guide {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 0;
  color: var(--ink-soft);
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  white-space: nowrap;
}

.guide-line {
  width: 2.75rem;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line-strong));
}

.guide-separator {
  color: var(--accent);
}

.header-actions {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 0.35rem;
}

.icon-action {
  min-height: 2.75rem;
  color: var(--ink-soft);
  transition:
    color 150ms var(--ease-out-quart),
    transform 100ms var(--ease-out-quart);
}

.icon-action svg,
.page-button svg {
  width: 1.15rem;
  height: 1.15rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon-action {
  display: grid;
  width: 2.75rem;
  padding: 0;
  border: 0;
  place-items: center;
  background: transparent;
  cursor: pointer;
}

.fullscreen-exit {
  display: none;
}

.icon-action[aria-pressed="true"] .fullscreen-enter {
  display: none;
}

.icon-action[aria-pressed="true"] .fullscreen-exit {
  display: block;
}

.reader-main {
  position: relative;
  width: 100%;
  min-width: 0;
  min-height: 0;
  display: grid;
  overflow: hidden;
  padding:
    clamp(1.5rem, 4.2vh, 3.8rem)
    max(clamp(2rem, 4.8vw, 5.5rem), env(safe-area-inset-right))
    clamp(1.25rem, 3.2vh, 2.8rem)
    max(clamp(2rem, 4.8vw, 5.5rem), env(safe-area-inset-left));
  place-items: center;
}

.reader-main::before {
  position: absolute;
  inset: 4% 7%;
  background: radial-gradient(ellipse 62% 48% at 50% 50%, oklch(34% 0.012 72 / 0.2), transparent 74%);
  content: "";
  pointer-events: none;
}

.reader-stage {
  position: relative;
  width: 100%;
  min-width: 0;
  height: 100%;
  min-height: 0;
  display: grid;
  place-items: center;
}

.book-frame {
  position: relative;
  isolation: isolate;
  width: min(100%, 107.5rem);
  max-width: min(90vw, 107.5rem);
  filter:
    drop-shadow(0 0.18rem 0.14rem oklch(2% 0.002 70 / 0.72))
    drop-shadow(0 1.65rem 1.85rem var(--shadow-ambient));
  opacity: 1;
  transform: translateY(-0.15rem);
  transition:
    opacity 420ms var(--ease-out-quart),
    transform 620ms var(--ease-out-quart),
    filter 260ms var(--ease-out-quart);
}

.book-frame::before {
  position: absolute;
  z-index: -3;
  inset: 0.18rem -0.18rem -0.5rem;
  border: 1px solid oklch(70% 0.018 68 / 0.2);
  background: linear-gradient(
    180deg,
    oklch(27% 0.017 61) 0%,
    oklch(19% 0.014 58) 72%,
    oklch(14% 0.011 56) 100%
  );
  box-shadow:
    0 0.82rem 1.7rem var(--shadow-deep),
    inset 0 -1px oklch(5% 0.006 58 / 0.72);
  content: "";
  pointer-events: none;
}

.book-frame::after {
  position: absolute;
  z-index: -2;
  right: 0.08rem;
  bottom: -0.6rem;
  left: 0.08rem;
  height: clamp(0.46rem, 1.15vw, 0.78rem);
  border-inline: 1px solid oklch(74% 0.015 76 / 0.36);
  background: repeating-linear-gradient(
    180deg,
    oklch(94% 0.009 83) 0 1px,
    oklch(83% 0.014 76) 1px 2px,
    oklch(90% 0.01 80) 2px 3px
  );
  box-shadow:
    inset 0 -1px oklch(49% 0.018 68 / 0.42),
    0 0.28rem 0.52rem oklch(2% 0.002 70 / 0.45);
  clip-path: polygon(0 0, 100% 0, 100% 72%, 75% 88%, 50% 100%, 25% 88%, 0 72%);
  content: "";
  pointer-events: none;
}

.app-shell[data-mode="loading"] .book-frame {
  opacity: 0.12;
  transform: translateY(0.8rem);
}

.app-shell[data-mode="loading"] .book-contour,
.app-shell[data-mode="loading"] .spine-shadow {
  display: none;
}

#book {
  width: 100%;
  margin-inline: auto;
}

#book:not(.stf__parent) .book-page {
  display: none;
}

.book-page {
  overflow: hidden;
  background: var(--paper);
  user-select: none;
}

.page-image {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: var(--paper);
  pointer-events: none;
  -webkit-user-drag: none;
}

.page-fallback {
  position: absolute;
  inset: 0;
  display: none;
  place-items: center;
  color: var(--page-ink);
  background: var(--paper);
  font-family: var(--font-display);
  letter-spacing: 0.08em;
}

.book-page.is-error .page-image {
  display: none;
}

.book-page.is-error .page-fallback {
  display: grid;
}

.book-contour {
  position: absolute;
  z-index: 11;
  inset: 0;
  background: linear-gradient(
    90deg,
    oklch(34% 0.018 62 / 0.035) 0%,
    transparent 0.7%,
    transparent 48.3%,
    oklch(99% 0.004 84 / 0.045) 48.9%,
    oklch(31% 0.018 61 / 0.07) 49.72%,
    transparent 50%,
    oklch(31% 0.018 61 / 0.065) 50.28%,
    oklch(99% 0.004 84 / 0.045) 51.1%,
    transparent 51.7%,
    transparent 99.3%,
    oklch(34% 0.018 62 / 0.035) 100%
  );
  opacity: 1;
  pointer-events: none;
  transition: opacity 180ms var(--ease-out-quart);
}

.spine-shadow {
  position: absolute;
  z-index: 12;
  top: 0;
  bottom: 0;
  left: 50%;
  width: clamp(0.85rem, 2vw, 2.2rem);
  background: linear-gradient(
    90deg,
    transparent 0%,
    oklch(24% 0.018 62 / 0.025) 24%,
    oklch(22% 0.018 62 / 0.08) 43%,
    oklch(18% 0.015 62 / 0.16) 49%,
    oklch(95% 0.009 81 / 0.11) 52%,
    oklch(27% 0.017 64 / 0.035) 64%,
    transparent 100%
  );
  opacity: 0.66;
  pointer-events: none;
  transform: translateX(-50%);
  transition: opacity 180ms var(--ease-out-quart);
  mix-blend-mode: multiply;
}

.book-frame:not([data-turn-state="read"]) .book-contour,
.book-frame:not([data-turn-state="read"]) .spine-shadow {
  opacity: 0;
  transition: none;
}

.loading-cover,
.reader-error {
  position: absolute;
  z-index: 30;
  display: grid;
  justify-items: center;
  gap: 0.8rem;
  max-width: 25rem;
  padding: 1.5rem;
  text-align: center;
}

.loading-cover {
  color: var(--ink-soft);
  font-family: var(--font-display);
  font-size: 0.88rem;
  letter-spacing: 0.16em;
  transition: opacity 260ms var(--ease-out-quart);
}

.loading-cover.is-hidden {
  opacity: 0;
  pointer-events: none;
}

.loading-rule {
  position: relative;
  width: 5.5rem;
  height: 1px;
  overflow: hidden;
  background: var(--line);
}

.loading-rule::after {
  position: absolute;
  inset: 0;
  background: var(--accent);
  content: "";
  transform: translateX(-100%);
  animation: loading-rule 1.35s var(--ease-in-out) infinite;
}

.reader-error {
  color: var(--ink);
  background: var(--surface);
  border-block: 1px solid var(--line-strong);
  line-height: 1.65;
}

.reader-error strong {
  color: var(--danger);
  font-family: var(--font-display);
  font-size: 1.15rem;
}

.reader-controls {
  position: relative;
  z-index: 10;
  display: grid;
  grid-template-columns: minmax(8rem, 1fr) minmax(15rem, 36rem) minmax(8rem, 1fr);
  align-items: center;
  gap: clamp(1rem, 3vw, 3rem);
  min-height: clamp(5.25rem, 9vh, 6.25rem);
  padding:
    0.65rem
    max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-right))
    max(0.65rem, env(safe-area-inset-bottom))
    max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-left));
}

.reader-controls::before {
  position: absolute;
  top: 0;
  right: max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-right));
  left: max(clamp(1.5rem, 3.75vw, 4rem), env(safe-area-inset-left));
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line) 12%, var(--line) 88%, transparent);
  content: "";
}

.page-button {
  position: relative;
  display: inline-flex;
  min-height: 2.9rem;
  align-items: center;
  gap: 0.7rem;
  padding: 0.45rem 0.55rem;
  border: 0;
  color: var(--ink-soft);
  background: transparent;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  transition:
    color 150ms var(--ease-out-quart),
    transform 100ms var(--ease-out-quart),
    opacity 150ms var(--ease-out-quart);
}

.page-button--previous {
  justify-self: start;
}

.page-button--next {
  justify-self: end;
}

.page-button--previous::before,
.page-button--next::after {
  position: absolute;
  top: 50%;
  width: 1px;
  height: 2.35rem;
  background: var(--line-strong);
  content: "";
  transform: translateY(-50%);
}

.page-button--previous::before {
  left: -0.7rem;
}

.page-button--next::after {
  right: -0.7rem;
}

.page-button:active:not(:disabled) {
  transform: translateY(1px);
}

.page-button:disabled {
  cursor: not-allowed;
  opacity: 0.3;
}

.reading-progress {
  display: grid;
  gap: 0.42rem;
  min-width: 0;
}

.page-readout {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 0.7rem;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.12em;
}

.view-mode {
  color: var(--accent-dark);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
}

#pageRange {
  --progress: 0%;
  width: 100%;
  height: 2rem;
  margin: 0;
  appearance: none;
  background: transparent;
  cursor: pointer;
}

#pageRange:disabled {
  cursor: not-allowed;
  opacity: 0.35;
}

#pageRange::-webkit-slider-runnable-track {
  height: 1px;
  background: linear-gradient(
    to right,
    var(--accent-dark) 0 var(--progress),
    var(--track) var(--progress) 100%
  );
}

#pageRange::-moz-range-track {
  height: 1px;
  background: var(--track);
}

#pageRange::-moz-range-progress {
  height: 1px;
  background: var(--accent-dark);
}

#pageRange::-webkit-slider-thumb {
  width: 0.8rem;
  height: 0.8rem;
  margin-top: -0.37rem;
  appearance: none;
  border: 2px solid var(--control-surface);
  border-radius: 50%;
  background: var(--accent-dark);
  box-shadow: 0 0 0 1px var(--accent-dark);
}

#pageRange::-moz-range-thumb {
  width: 0.65rem;
  height: 0.65rem;
  border: 2px solid var(--control-surface);
  border-radius: 50%;
  background: var(--accent-dark);
  box-shadow: 0 0 0 1px var(--accent-dark);
}

.orientation-notice {
  position: fixed;
  z-index: 120;
  inset: 0;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 1.5rem;
  padding:
    max(2rem, env(safe-area-inset-top))
    max(2rem, env(safe-area-inset-right))
    max(2rem, env(safe-area-inset-bottom))
    max(2rem, env(safe-area-inset-left));
  color: var(--ink);
  background:
    radial-gradient(circle at 50% 42%, oklch(27% 0.012 70), transparent 55%),
    var(--canvas-deep);
  text-align: center;
}

.orientation-notice::before {
  position: absolute;
  inset: 1.25rem;
  border: 1px solid var(--line);
  content: "";
  pointer-events: none;
}

.orientation-icon {
  width: 4.5rem;
  height: 4.5rem;
  fill: none;
  stroke: var(--accent-dark);
  stroke-width: 1.25;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.orientation-copy {
  display: grid;
  gap: 0.65rem;
}

.orientation-copy strong {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 6vw, 2rem);
  font-weight: 400;
  letter-spacing: 0.12em;
}

.orientation-copy span {
  color: var(--ink-soft);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
}

.noscript-message {
  position: fixed;
  z-index: 90;
  inset: auto 1rem 1rem;
  padding: 1rem;
  color: var(--canvas-deep);
  background: var(--ink);
  text-align: center;
}

.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;
}

@keyframes loading-rule {
  0% {
    transform: translateX(-100%);
  }

  48%,
  52% {
    transform: translateX(0%);
  }

  100% {
    transform: translateX(100%);
  }
}

@media (hover: hover) {
  .icon-action:hover,
  .page-button:hover:not(:disabled) {
    color: var(--accent-dark);
  }

  .page-button--previous:hover:not(:disabled) svg {
    transform: translateX(-0.16rem);
  }

  .page-button--next:hover:not(:disabled) svg {
    transform: translateX(0.16rem);
  }

  .page-button svg {
    transition: transform 180ms var(--ease-out-quart);
  }

  .icon-action:hover {
    transform: translateY(-1px);
  }
}

@media (orientation: landscape) and (max-height: 32rem) {
  .app-shell {
    grid-template-rows: auto minmax(0, 1fr) auto;
  }

  .masthead {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0.75rem;
    min-height: 3.25rem;
    padding:
      max(0.35rem, env(safe-area-inset-top))
      max(0.65rem, env(safe-area-inset-right))
      0.3rem
      max(0.65rem, env(safe-area-inset-left));
  }

  .masthead::after {
    right: max(0.65rem, env(safe-area-inset-right));
    left: max(0.65rem, env(safe-area-inset-left));
  }

  .book-identity {
    gap: 0.72rem;
  }

  .book-mark {
    width: 2rem;
    height: 2.1rem;
    font-size: 1.72rem;
  }

  .book-mark::before {
    right: -0.34rem;
  }

  .book-mark::after {
    right: -0.55rem;
    bottom: 0.02rem;
    width: 0.3rem;
    height: 0.3rem;
  }

  .book-meta {
    gap: 0;
  }

  .book-title {
    font-size: 0.78rem;
    letter-spacing: 0.14em;
  }

  .book-subtitle {
    font-size: 0.48rem;
    letter-spacing: 0.16em;
  }

  .reading-guide {
    display: none;
  }

  .icon-action {
    width: 2.75rem;
    min-height: 2.75rem;
  }

  .reader-main {
    padding:
      0.2rem
      max(0.45rem, env(safe-area-inset-right))
      0.25rem
      max(0.45rem, env(safe-area-inset-left));
  }

  .reader-main::before {
    inset: 0 3%;
  }

  .book-frame {
    max-width: calc(
      100vw - max(1rem, calc(env(safe-area-inset-left) + env(safe-area-inset-right)))
    );
    filter:
      drop-shadow(0 0.1rem 0.1rem oklch(2% 0.002 70 / 0.72))
      drop-shadow(0 0.72rem 0.72rem oklch(2% 0.002 70 / 0.58));
    transform: none;
  }

  .book-frame::before {
    inset: 0.1rem -0.1rem -0.32rem;
  }

  .book-frame::after {
    bottom: -0.38rem;
    height: 0.42rem;
  }

  .reader-controls {
    grid-template-columns: minmax(6rem, 1fr) minmax(12rem, 24rem) minmax(6rem, 1fr);
    gap: clamp(0.35rem, 2vw, 1rem);
    min-height: 3.65rem;
    padding:
      0.2rem
      max(0.75rem, env(safe-area-inset-right))
      max(0.2rem, env(safe-area-inset-bottom))
      max(0.75rem, env(safe-area-inset-left));
  }

  .reader-controls::before {
    right: max(0.75rem, env(safe-area-inset-right));
    left: max(0.75rem, env(safe-area-inset-left));
  }

  .page-button {
    min-height: 3rem;
    gap: 0.35rem;
    padding: 0.2rem;
    font-size: 0.66rem;
    letter-spacing: 0.1em;
  }

  .page-button--previous::before,
  .page-button--next::after {
    height: 1.65rem;
  }

  .page-button--previous::before {
    left: -0.3rem;
  }

  .page-button--next::after {
    right: -0.3rem;
  }

  .reading-progress {
    gap: 0;
  }

  .page-readout {
    font-size: 0.68rem;
  }

  #pageRange {
    height: 1.2rem;
  }

  #pageRange::-webkit-slider-thumb {
    width: 0.68rem;
    height: 0.68rem;
    margin-top: -0.31rem;
  }

  #pageRange::-moz-range-thumb {
    width: 0.55rem;
    height: 0.55rem;
  }
}

@media (orientation: landscape) and (max-height: 23rem) {
  .book-subtitle {
    display: none;
  }

  .masthead {
    min-height: 3rem;
  }

  .reader-controls {
    min-height: 3.35rem;
  }
}

@media (pointer: coarse) {
  .icon-action,
  .page-button {
    min-height: 3rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .spine-shadow {
    opacity: 0.42;
  }
}

.app-shell:fullscreen {
  width: 100%;
  height: 100%;
  min-height: 100%;
  background:
    radial-gradient(ellipse 74% 66% at 50% 48%, oklch(31% 0.012 72 / 0.36), transparent 69%),
    linear-gradient(180deg, oklch(20% 0.009 70), var(--canvas-deep));
}