/* =============================================================================
   PDF Flipbook — two-page book spread with 3D page-turn animation.
   All rules scoped to .pdf-flipbook-wrapper.
   ============================================================================= */

.pdf-flipbook-wrapper {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 14px;
  color: #777;
  -webkit-user-select: none;
  user-select: none;
}

.pdf-flipbook-wrapper * {
  box-sizing: border-box;
}

/* ── Inner row: [arrow] [book] [arrow] ──────────────────────────────────────── */

.pdf-flipbook-inner {
  display: inline-flex;
  flex-direction: row;
  align-items: center;
  gap: 16px;
  max-width: 100%;
}

/* ── Book container ──────────────────────────────────────────────────────────── */

.pdf-flipbook-book {
  position: relative;
  display: inline-block;
  flex-shrink: 0;
  /* width/height are set by JS to (2×pageW) × pageH */
  background: #f2ede6;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25), 0 2px 6px rgba(0, 0, 0, 0.15);
  border-radius: 2px;
  /* No overflow:hidden — it flattens preserve-3d in some browsers */
  perspective: 2000px;
  perspective-origin: 50% 50%;
  cursor: grab;
  min-width: 80px;
  min-height: 80px;
  line-height: 0;
}

.pdf-flipbook-book--dragging,
.pdf-flipbook-book:active {
  cursor: grabbing;
}

/* ── Static page panels ──────────────────────────────────────────────────────── */

.pdf-flipbook-panel {
  position: absolute;
  top: 0;
  overflow: hidden;
  /* width, height, left set by JS */
}

.pdf-flipbook-panel--left {
  left: 0;
}
/* .pdf-flipbook-panel--right: left set dynamically by JS */

/* ── Spine ───────────────────────────────────────────────────────────────────── */

.pdf-flipbook-spine {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  background: linear-gradient(
    to right,
    rgba(0, 0, 0, 0.20) 0%,
    rgba(255, 255, 255, 0.12) 50%,
    rgba(0, 0, 0, 0.16) 100%
  );
  z-index: 5;
  pointer-events: none;
}

/* ── Page canvases ───────────────────────────────────────────────────────────── */

.pdf-flipbook-page {
  display: block;
  /* CSS width/height and canvas attributes are both set by JS */
}

/* ── Flip card ───────────────────────────────────────────────────────────────── */

.pdf-flipbook-flip-card {
  position: absolute;
  /* top / left / width / height set by JS before each flip */
  transform-style: preserve-3d;
  z-index: 10;
  display: none;
  pointer-events: none;
}

.pdf-flipbook-flip-card--visible {
  display: block;
}

/* Pivot from the LEFT edge of the card = the spine, when going forward */
.pdf-flipbook-flip-card--forward {
  transform-origin: left center;
}

/* Pivot from the RIGHT edge of the card = the spine, when going backward */
.pdf-flipbook-flip-card--backward {
  transform-origin: right center;
}

/* ── Flip faces ──────────────────────────────────────────────────────────────── */

.pdf-flipbook-flip-face {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* front: visible at 0 ° — shows the page being turned */
.pdf-flipbook-flip-face--front {
  /* no extra transform needed */
}

/* back: pre-rotated 180 ° so it reads correctly when the card completes its turn */
.pdf-flipbook-flip-face--back {
  transform: rotateY(180deg);
}

/* ── Flip animations ─────────────────────────────────────────────────────────── */

@keyframes pdf-flipbook-turn-forward {
  from { transform: rotateY(0deg);    }
  to   { transform: rotateY(-180deg); }
}

@keyframes pdf-flipbook-turn-backward {
  from { transform: rotateY(0deg);   }
  to   { transform: rotateY(180deg); }
}

.pdf-flipbook-flip-card--animating-forward {
  animation: pdf-flipbook-turn-forward 0.5s cubic-bezier(0.45, 0, 0.55, 1) forwards;
}

.pdf-flipbook-flip-card--animating-backward {
  animation: pdf-flipbook-turn-backward 0.5s cubic-bezier(0.45, 0, 0.55, 1) forwards;
}

/* ── Navigation arrows ───────────────────────────────────────────────────────── */

.pdf-flipbook-nav {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  padding: 10px;
  margin: 0;
  background: rgba(255, 255, 255, 0.82);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  color: #555;
  opacity: 0.80;
  outline: none;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.18);
  -webkit-tap-highlight-color: transparent;
  transition: background .15s ease-in, color .15s ease-in, opacity .15s ease-in, box-shadow .15s ease-in;
}

.pdf-flipbook-nav:hover {
  background: rgba(255, 255, 255, 0.97);
  color: #000;
  opacity: 1;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
  transition: background .15s ease-out, color .15s ease-out, opacity .15s ease-out, box-shadow .15s ease-out;
}

.pdf-flipbook-nav:active {
  background: rgba(235, 235, 235, 0.97);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
}

.pdf-flipbook-nav__icon {
  display: block;
  width: 14px;
  height: 22px;
  stroke: currentColor;
  fill: none;
  flex-shrink: 0;
}

/* visibility:hidden keeps the flex space so the book stays centered */
.pdf-flipbook-nav--hidden {
  visibility: hidden;
  pointer-events: none;
}

/* ── Loader ─────────────────────────────────────────────────────────────────── */

.pdf-flipbook-loader {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 50px;
  height: 50px;
  transform: translate(-50%, -50%);
  z-index: 20;
  display: none;
}

.pdf-flipbook-loader--visible {
  display: block;
}

.pdf-flipbook-loader__inner {
  position: relative;
  width: 100px;
  height: 100px;
  transform: scale(0.5);
  transform-origin: 0 0;
}

@keyframes pdf-flipbook-dot-pulse {
  0%   { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.pdf-flipbook-loader__dot {
  position: absolute;
  width: 35px;
  height: 35px;
  animation: pdf-flipbook-dot-pulse 1s cubic-bezier(0, 0.5, 0.5, 1) infinite;
}
.pdf-flipbook-loader__dot:nth-child(1) { top: 10px; left: 10px; background: #353535; animation-delay: -0.3s; }
.pdf-flipbook-loader__dot:nth-child(2) { top: 10px; left: 55px; background: #666666; animation-delay: -0.2s; }
.pdf-flipbook-loader__dot:nth-child(3) { top: 55px; left: 10px; background: #9b9b9b; animation-delay:  0.0s; }
.pdf-flipbook-loader__dot:nth-child(4) { top: 55px; left: 55px; background: #d4d4d4; animation-delay: -0.1s; }

/* Loading caption */
.pdf-flipbook-loading-text {
  position: absolute;
  top: calc(50% + 40px);
  left: 50%;
  transform: translateX(-50%);
  background: #fff;
  border: 1px solid #ddd;
  padding: 5px 10px;
  border-radius: 5px;
  font-style: italic;
  font-size: 12px;
  white-space: nowrap;
  z-index: 20;
  display: none;
  color: #777;
}

.pdf-flipbook-loading-text--visible {
  display: block;
}

/* ── Swipe hint (touch devices) ─────────────────────────────────────────────── */

.pdf-flipbook-swipe-hint {
  position: absolute;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(60, 60, 60, 0.8);
  color: #fff;
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 11px;
  letter-spacing: 0.04em;
  pointer-events: none;
  z-index: 10;
  opacity: 1;
  transition: opacity 0.5s ease-out;
  white-space: nowrap;
  display: none;
}

.pdf-flipbook-swipe-hint--visible {
  display: block;
}

.pdf-flipbook-swipe-hint--fade {
  opacity: 0;
}

/* ── Error message ───────────────────────────────────────────────────────────── */

.pdf-flipbook-error {
  padding: 16px 20px;
  text-align: center;
  color: #842029;
  background: #f8d7da;
  border: 1px solid #f5c2c7;
  border-radius: 4px;
  font-size: 13px;
}

/* ── Mobile: arrows overlaid inside the book ─────────────────────────────────── */

@media (max-width: 767px) {
  .pdf-flipbook-inner {
    position: relative;
    gap: 0;
    /* clip the flip card that temporarily extends beyond the book during 3D turn */
    overflow: hidden;
    /* padding lets the book shadow show on all sides without being clipped */
    padding: 12px;
  }

  .pdf-flipbook-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    z-index: 10;
    width: 36px;
    height: 36px;
    padding: 7px;
    background: rgba(255, 255, 255, 0.72);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.18);
  }

  .pdf-flipbook-nav--prev { left: 8px;  }
  .pdf-flipbook-nav--next { right: 8px; }

  .pdf-flipbook-nav__icon {
    width: 10px;
    height: 16px;
  }

  .pdf-flipbook-nav--hidden {
    visibility: hidden;
    pointer-events: none;
  }
}