/* Immersive desktop spread for Aasta Books.
   The semantic reader stays authoritative; this layer only mirrors already-
   paginated pages into a roomy two-page spread and animates page turns. */

.reader-view.flipbook-enabled {
  --flipbook-width: min(1480px, calc(100vw - clamp(92px, 9vw, 170px)));
  --flipbook-height: min(780px, calc(100dvh - 188px));
  --flipbook-pad-x: clamp(30px, 3.2vw, 58px);
  --flipbook-pad-y: clamp(28px, 3.8vh, 52px);
}

.reader-view.flipbook-spread-mode .reader-topbar {
  min-height: calc(64px + var(--safe-top));
  padding-top: calc(10px + var(--safe-top));
  padding-bottom: 10px;
  background: color-mix(in srgb, var(--reader-bg) 96%, transparent);
  border-bottom-color: color-mix(in srgb, var(--reader-border) 72%, transparent);
  backdrop-filter: blur(14px);
}

.reader-view.flipbook-spread-mode .icon-button.labelled {
  width: 42px;
  min-width: 42px;
  height: 42px;
  padding: 0;
  border-radius: 11px;
}

.reader-view.flipbook-spread-mode .icon-button.labelled small {
  display: none;
}

.reader-view.flipbook-spread-mode .reader-stage {
  inset: calc(64px + var(--safe-top)) 0 calc(62px + var(--safe-bottom));
  grid-template-columns: clamp(30px, 4vw, 58px) minmax(0, 1fr) clamp(30px, 4vw, 58px);
}

.reader-view.flipbook-spread-mode .pages-viewport {
  overflow: visible;
  padding: 0 0 48px;
  display: grid;
  place-items: center;
  perspective: 2400px;
  perspective-origin: 50% 47%;
  isolation: isolate;
}

.reader-view.flipbook-spread-mode .pages-track {
  position: absolute;
  inset: 0;
  opacity: 0;
  pointer-events: none;
  transition: none !important;
}

.reader-view.flipbook-spread-mode .measure-page {
  width: calc(var(--flipbook-width) / 2);
  height: var(--flipbook-height);
  padding: var(--flipbook-pad-y) var(--flipbook-pad-x) 44px;
  border-radius: 2px;
}

.flipbook-spread {
  position: relative;
  z-index: 2;
  width: var(--flipbook-width);
  height: var(--flipbook-height);
  max-width: calc(100% - 10px);
  max-height: calc(100% - 52px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  transform-style: preserve-3d;
  perspective: 2400px;
  filter: drop-shadow(0 10px 18px rgba(42, 28, 19, .10));
  user-select: text;
}

.flipbook-spread[hidden] {
  display: none !important;
}

/* The old faux leather cover and stacked paper edges made the reader look like
   a small CSS demo. The spread now behaves like a modern web reader: full-size
   pages with only a restrained seam and shadow. */
.flipbook-cover-underlay,
.flipbook-spread::before,
.flipbook-spread::after {
  display: none;
}

.flipbook-page-slot {
  position: relative;
  z-index: 1;
  min-width: 0;
  height: 100%;
  transform-style: preserve-3d;
}

.flipbook-physical-page,
.flipbook-leaf-face {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: var(--flipbook-pad-y) var(--flipbook-pad-x) 44px;
  overflow: hidden;
  background: var(--reader-page);
  color: var(--reader-text);
  border: 1px solid color-mix(in srgb, var(--reader-border) 80%, transparent);
  box-shadow: none;
  transform: none;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  user-select: text;
}

.flipbook-left-page {
  border-radius: 10px 0 0 10px;
  border-right-color: color-mix(in srgb, var(--reader-border) 38%, transparent);
  box-shadow: inset -14px 0 22px -24px rgba(52, 34, 24, .20);
}

.flipbook-right-page {
  border-radius: 0 10px 10px 0;
  border-left-color: color-mix(in srgb, var(--reader-border) 38%, transparent);
  box-shadow: inset 14px 0 22px -24px rgba(52, 34, 24, .20);
}

.flipbook-physical-page::after,
.flipbook-leaf-face::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 3;
  pointer-events: none;
  background: none;
}

.flipbook-left-page::after {
  background: linear-gradient(270deg, rgba(59,39,28,.045), transparent 4.5%);
}

.flipbook-right-page::after {
  background: linear-gradient(90deg, rgba(59,39,28,.045), transparent 4.5%);
}

.flipbook-spine {
  position: absolute;
  z-index: 8;
  top: 1px;
  bottom: 1px;
  left: 50%;
  width: 1px;
  transform: translateX(-50%);
  pointer-events: none;
  background: color-mix(in srgb, var(--reader-border) 64%, transparent);
  opacity: .72;
}

.reader-view[data-theme='night'] .flipbook-spine {
  opacity: .9;
}

.flipbook-physical-page p,
.flipbook-leaf-face p {
  max-width: 58ch;
  margin-left: auto;
  margin-right: auto;
}

.flipbook-physical-page .chapter-heading,
.flipbook-leaf-face .chapter-heading {
  max-width: 58ch;
}

.flipbook-physical-page .chapter-heading h1,
.flipbook-leaf-face .chapter-heading h1 {
  font-size: clamp(32px, 2.5vw, 48px);
}

.flipbook-left-page .page-number {
  left: var(--flipbook-pad-x);
  right: auto;
}

.flipbook-right-page .page-number {
  left: auto;
  right: var(--flipbook-pad-x);
}

.flipbook-blank-page {
  display: grid;
  place-items: center;
}

.flipbook-blank-mark {
  color: color-mix(in srgb, var(--reader-muted) 30%, transparent);
  font: 700 9px/1 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .42em;
  user-select: none;
}

.flipbook-turn-leaf {
  position: absolute;
  z-index: 30;
  top: 0;
  bottom: 0;
  width: 50%;
  transform-style: preserve-3d;
  pointer-events: none;
  will-change: transform;
}

.flipbook-turn-forward {
  right: 0;
  transform-origin: left center;
  transform: rotateY(0deg);
}

.flipbook-turn-previous {
  left: 0;
  transform-origin: right center;
  transform: rotateY(0deg);
}

.flipbook-leaf-face {
  position: absolute;
  inset: 0;
}

.flipbook-leaf-front {
  z-index: 2;
}

.flipbook-turn-forward .flipbook-leaf-back {
  transform: rotateY(180deg);
}

.flipbook-turn-previous .flipbook-leaf-back {
  transform: rotateY(-180deg);
}

.flipbook-turn-forward.flipbook-leaf-animate {
  animation: aastaPhysicalPageForward 320ms cubic-bezier(.22,.63,.18,1) both;
}

.flipbook-turn-previous.flipbook-leaf-animate {
  animation: aastaPhysicalPagePrevious 320ms cubic-bezier(.22,.63,.18,1) both;
}

.flipbook-turn-leaf::after {
  content: '';
  position: absolute;
  z-index: 6;
  inset: 0;
  opacity: 0;
  pointer-events: none;
  backface-visibility: hidden;
}

.flipbook-turn-forward::after {
  background: linear-gradient(90deg, rgba(42,27,19,.18), transparent 34%);
}

.flipbook-turn-previous::after {
  background: linear-gradient(270deg, rgba(42,27,19,.18), transparent 34%);
}

.flipbook-turn-leaf.flipbook-leaf-animate::after {
  animation: aastaFoldShadow 320ms ease both;
}

@keyframes aastaPhysicalPageForward {
  0% {
    transform: perspective(2300px) rotateY(0deg) translateZ(0);
    filter: brightness(1);
    box-shadow: 0 2px 4px rgba(38,24,17,.06);
  }
  20% {
    transform: perspective(2300px) rotateY(-28deg) translateZ(7px);
    filter: brightness(.99);
    box-shadow: 16px 8px 26px rgba(38,24,17,.13);
  }
  48% {
    transform: perspective(2300px) rotateY(-88deg) translateZ(12px);
    filter: brightness(.88);
    box-shadow: 28px 10px 38px rgba(38,24,17,.19);
  }
  52% {
    transform: perspective(2300px) rotateY(-94deg) translateZ(12px);
    filter: brightness(.89);
  }
  78% {
    transform: perspective(2300px) rotateY(-151deg) translateZ(6px);
    filter: brightness(.98);
    box-shadow: -14px 7px 24px rgba(38,24,17,.12);
  }
  100% {
    transform: perspective(2300px) rotateY(-180deg) translateZ(0);
    filter: brightness(1);
    box-shadow: none;
  }
}

@keyframes aastaPhysicalPagePrevious {
  0% {
    transform: perspective(2300px) rotateY(0deg) translateZ(0);
    filter: brightness(1);
    box-shadow: 0 2px 4px rgba(38,24,17,.06);
  }
  20% {
    transform: perspective(2300px) rotateY(28deg) translateZ(7px);
    filter: brightness(.99);
    box-shadow: -16px 8px 26px rgba(38,24,17,.13);
  }
  48% {
    transform: perspective(2300px) rotateY(88deg) translateZ(12px);
    filter: brightness(.88);
    box-shadow: -28px 10px 38px rgba(38,24,17,.19);
  }
  52% {
    transform: perspective(2300px) rotateY(94deg) translateZ(12px);
    filter: brightness(.89);
  }
  78% {
    transform: perspective(2300px) rotateY(151deg) translateZ(6px);
    filter: brightness(.98);
    box-shadow: 14px 7px 24px rgba(38,24,17,.12);
  }
  100% {
    transform: perspective(2300px) rotateY(180deg) translateZ(0);
    filter: brightness(1);
    box-shadow: none;
  }
}

@keyframes aastaFoldShadow {
  0%, 100% { opacity: 0; }
  35% { opacity: .32; }
  50% { opacity: .48; }
  70% { opacity: .24; }
}

/* Navigation is intentionally quiet: arrows sit at the page edges and the
   bottom status is a compact progress readout instead of instructional copy. */
.reader-view.flipbook-spread-mode .page-controls {
  left: 50%;
  right: auto;
  bottom: 0;
  width: min(var(--flipbook-width), calc(100% - 10px));
  height: 100%;
  min-height: 0;
  transform: translateX(-50%);
  display: block;
  pointer-events: none;
}

.reader-view.flipbook-spread-mode .page-controls button {
  position: absolute;
  top: calc(50% - 24px);
  width: 42px;
  height: 58px;
  padding: 0;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 999px;
  background: color-mix(in srgb, var(--reader-bg) 84%, transparent);
  color: var(--reader-muted);
  font-size: 28px;
  line-height: 1;
  opacity: .46;
  pointer-events: auto;
  transition: opacity .18s ease, background .18s ease, color .18s ease;
}

.reader-view.flipbook-spread-mode .page-controls button:first-child {
  left: 12px;
}

.reader-view.flipbook-spread-mode .page-controls button:last-child {
  right: 12px;
}

.reader-view.flipbook-spread-mode .page-controls button:hover,
.reader-view.flipbook-spread-mode .page-controls button:focus-visible {
  opacity: 1;
  color: var(--reader-text);
  background: color-mix(in srgb, var(--reader-page) 94%, transparent);
}

.reader-view.flipbook-spread-mode .page-controls button:disabled {
  opacity: .12;
}

.reader-view.flipbook-spread-mode .page-controls p {
  position: absolute;
  left: 50%;
  bottom: 10px;
  transform: translateX(-50%);
  min-width: max-content;
  margin: 0;
  font-size: 10px;
  letter-spacing: .04em;
}

.reader-view.flipbook-spread-mode .chapter-edge {
  z-index: 12;
  opacity: .22;
  transition: opacity .18s ease, color .18s ease;
}

.reader-view.flipbook-spread-mode .chapter-edge:hover,
.reader-view.flipbook-spread-mode .chapter-edge:focus-visible {
  opacity: .8;
  background: transparent;
}

.reader-view.flipbook-spread-mode .chapter-edge span {
  font-size: 34px;
}

.reader-view.flipbook-spread-mode .chapter-edge small {
  display: none;
}

.reader-view.flipbook-spread-mode .reader-footer {
  min-height: calc(62px + var(--safe-bottom));
  padding: 9px calc(30px + var(--safe-right)) calc(9px + var(--safe-bottom)) calc(30px + var(--safe-left));
  background: color-mix(in srgb, var(--reader-bg) 96%, transparent);
  border-top-color: color-mix(in srgb, var(--reader-border) 72%, transparent);
  backdrop-filter: blur(14px);
}

.reader-view.flipbook-spread-mode .reader-hint {
  display: none;
}

.reader-view.flipbook-spread-mode .progress-meta {
  position: relative;
  min-height: 18px;
  align-items: center;
  justify-content: center;
}

.reader-view.flipbook-spread-mode #chapterProgressLabel,
.reader-view.flipbook-spread-mode #bookProgressLabel {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.reader-view.flipbook-spread-mode #sessionStatus[hidden] {
  display: none !important;
}

.reader-view.flipbook-spread-mode #sessionStatus:not([hidden]) {
  position: absolute;
  left: 0;
  border: 0;
  background: transparent;
  color: var(--reader-muted);
  font-size: 10px;
}

.reader-view.flipbook-spread-mode .reader-page-summary {
  color: var(--reader-muted);
  font-size: 10px;
  letter-spacing: .02em;
}

.reader-view.flipbook-spread-mode .progress-track {
  width: min(980px, 82vw);
  height: 2px;
  margin: 7px auto 0;
}

.reader-view.flipbook-is-turning .flipbook-page-slot {
  pointer-events: none;
}

@media (max-height: 700px) and (min-width: 900px) {
  .reader-view.flipbook-enabled {
    --flipbook-height: calc(100dvh - 176px);
    --flipbook-pad-y: clamp(22px, 3vh, 34px);
  }

  .reader-view.flipbook-spread-mode .pages-viewport {
    padding-bottom: 40px;
  }
}

@media (max-width: 899px) {
  .reader-view.flipbook-enabled .pages-viewport {
    perspective: 1500px;
  }

  .reader-view.flipbook-enabled .page-sheet:not(.measure-page) {
    box-shadow: 0 8px 18px rgba(35,22,15,.10);
  }
}

@media (prefers-reduced-motion: reduce) {
  .flipbook-turn-leaf,
  .flipbook-turn-leaf::after {
    animation: none !important;
    transition: none !important;
  }

  .reader-view.flipbook-enabled .pages-track,
  .reader-view.flipbook-enabled .page-sheet {
    scroll-behavior: auto;
    transition: none !important;
  }
}