/* ═══════════════════════════════════════════════════
   PDF flipbook (assets/js/flipbook.js)
   - .flipbook            inline block (rautomead/flipbook)
   - .flipbook-lightbox   full-screen viewer (Literature "Read online" +
                          the inline block's fullscreen button)
   StPageFlip positions the pages itself via inline styles; we only style
   the page surface, the chrome and the states.
   ═══════════════════════════════════════════════════ */

/* ── Inline block ── */
.flipbook {
  margin: clamp(2rem, 5vw, 3.5rem) auto;
  max-width: 1100px;
  padding: 0 var(--space-section-x);
}

.flipbook.alignwide { max-width: 1400px; }
.flipbook.alignfull { max-width: none; }

.flipbook__frame {
  position: relative;
  background: var(--color-dark-surface);
  border-radius: var(--border-radius);
  padding: clamp(1rem, 3vw, 2rem);
  outline: none;
}

.flipbook__frame:focus-visible {
  box-shadow: 0 0 0 3px var(--color-primary);
}

.flipbook__caption {
  margin: 0.9rem 0 0;
  text-align: center;
  font-size: 0.875rem;
  color: inherit;
  opacity: 0.7;
}

/* ── Stage + book (shared) ── */
.flipbook__stage {
  position: relative;
  width: 100%;
  min-height: 240px;
}

.flipbook__book-wrap {
  max-width: 100%;
  margin: 0 auto;
}

.flipbook__book {
  width: 100%;
}

.flipbook__page {
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.06);
}

.flipbook__page canvas {
  display: block;
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 100%;
}

/* Skeleton shimmer until the page bitmap has rendered. */
.flipbook__page:not(.is-rendered)::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(110deg, #f2f2f2 30%, #fafafa 50%, #f2f2f2 70%);
  background-size: 200% 100%;
  animation: flipbook-shimmer 1.4s ease-in-out infinite;
}

@keyframes flipbook-shimmer {
  from { background-position: 200% 0; }
  to { background-position: -200% 0; }
}

/* ── Controls ── */
.flipbook__controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  margin-top: 1.25rem;
}

.flipbook__controls[hidden] { display: none; }

.flipbook__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 40px;
  padding: 0 1rem;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 700;
  line-height: 1;
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.25s ease, border-color 0.25s ease, opacity 0.25s ease;
}

.flipbook__btn:hover,
.flipbook__btn:focus-visible {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.flipbook__btn:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

.flipbook__btn:disabled {
  opacity: 0.3;
  cursor: default;
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.18);
}

.flipbook__btn--icon {
  width: 40px;
  padding: 0;
}

.flipbook__btn svg { flex-shrink: 0; }

/* Prev / next: large, high-contrast discs with a bold chevron. */
.flipbook__nav {
  width: 52px;
  height: 52px;
  min-height: 52px;
  padding: 0;
  color: #fff;
  background: rgba(255, 255, 255, 0.14);
  border: 1.5px solid rgba(255, 255, 255, 0.45);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.45);
}

.flipbook__nav svg {
  width: 26px;
  height: 26px;
  stroke-width: 2.5;
}

.flipbook__nav:hover:not(:disabled),
.flipbook__nav:focus-visible {
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.flipbook__nav:disabled {
  opacity: 0.25;
  box-shadow: none;
}

.flipbook__counter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 9.5rem;
  min-height: 44px;
  padding: 0 1.1rem;
  text-align: center;
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: rgba(255, 255, 255, 0.9);
  background: rgba(255, 255, 255, 0.08);
  border-radius: 999px;
  font-variant-numeric: tabular-nums;
}

/* ── States: fallback / loading / error ── */
.flipbook__fallback {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-text-body);
}

.flipbook__fallback a {
  color: var(--color-primary);
  font-weight: 700;
}

.flipbook.is-ready .flipbook__fallback,
.flipbook__stage.is-loading .flipbook__fallback { display: none; }

.flipbook__loading {
  display: none;
  position: absolute;
  left: 50%;
  top: 50%;
  width: 36px;
  height: 36px;
  margin: -18px 0 0 -18px;
  border: 3px solid rgba(255, 255, 255, 0.15);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: flipbook-spin 0.8s linear infinite;
}

.flipbook__stage.is-loading .flipbook__loading { display: block; }

@keyframes flipbook-spin { to { transform: rotate(360deg); } }

.flipbook__error {
  display: none;
  position: absolute;
  inset: 0;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 2rem;
  text-align: center;
  color: #fff;
}

.flipbook__error p { margin: 0; font-size: 1rem; }

.flipbook__stage.is-error .flipbook__error { display: flex; }

/* ── Editor placeholder (block preview has no JS) ── */
.flipbook__placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 3rem 2rem;
  text-align: center;
  color: #fff;
  background: var(--color-dark-surface);
  border: 1px dashed rgba(255, 255, 255, 0.25);
  border-radius: var(--border-radius);
}

.flipbook__placeholder-icon { color: var(--color-primary); }
.flipbook__placeholder strong { font-size: 1.05rem; }
.flipbook__placeholder span { font-size: 0.875rem; color: var(--color-text-muted); }

/* ── Lightbox ── */
.flipbook-lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0s linear 0.3s;
}

.flipbook-lightbox.is-open {
  opacity: 1;
  visibility: visible;
  transition: opacity 0.3s ease;
}

.flipbook-lightbox__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(8, 8, 8, 0.9);
  backdrop-filter: blur(8px);
}

.flipbook-lightbox__dialog {
  position: relative;
  height: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: clamp(0.75rem, 3vw, 2rem);
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 1rem;
  transform: translateY(16px) scale(0.98);
  transition: transform 0.35s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.flipbook-lightbox.is-open .flipbook-lightbox__dialog { transform: none; }

.flipbook-lightbox__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.flipbook-lightbox__title {
  margin: 0;
  min-width: 0;
  font-size: clamp(1rem, 2vw, 1.35rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #fff;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.flipbook-lightbox__bar-actions {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.flipbook-lightbox__stage {
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.flipbook-lightbox__controls { margin-top: 0; }

/* On wider screens the arrows float either side of the book, vertically
   centred on the stage; the counter stays in the bottom row. Below 760px they
   drop back into the bottom row (no room beside a portrait page). */
@media (min-width: 760px) {
  .flipbook-lightbox__dialog .flipbook__nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 60px;
    height: 60px;
    min-height: 60px;
    z-index: 5;
    background: rgba(24, 24, 24, 0.85);
  }

  .flipbook-lightbox__dialog .flipbook__nav svg {
    width: 30px;
    height: 30px;
  }

  .flipbook-lightbox__dialog .flipbook__nav--prev { left: clamp(0.5rem, 2vw, 1.5rem); }
  .flipbook-lightbox__dialog .flipbook__nav--next { right: clamp(0.5rem, 2vw, 1.5rem); }

  .flipbook-lightbox__dialog .flipbook__nav:hover:not(:disabled),
  .flipbook-lightbox__dialog .flipbook__nav:focus-visible {
    background: var(--color-primary);
    transform: translateY(-50%) scale(1.06);
  }
}

@media (max-width: 640px) {
  .flipbook-lightbox__download span { display: none; }
  .flipbook-lightbox__download { width: 40px; padding: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .flipbook-lightbox,
  .flipbook-lightbox__dialog { transition: none; }
  .flipbook__loading,
  .flipbook__page:not(.is-rendered)::after { animation: none; }
}