/* Each leaf is one opaque composited surface. Sibling chapters must never
   occupy a shared coplanar preserve-3d scene (customer's text ghosting video). */
html.book-motion-ready .content-book__pages { transform-style: flat; }
html.book-motion-ready [data-book-page] {
  transform-style: flat;
  contain: paint;
  background-color: #090908;
}
html.book-motion-ready [data-book-page][data-book-paint="hidden"] {
  visibility: hidden;
  pointer-events: none;
  will-change: auto;
}
html.book-motion-ready [data-book-page] > .vision-grid,
html.book-motion-ready [data-book-page] > .content-shell {
  transform: translateY(var(--book-content-y));
  backface-visibility: hidden;
}
html[data-customer-revision="v15"] .book-back-cover {
  --book-art: none;
  min-height: 85svh;
  background: radial-gradient(ellipse at 50% 38%, #29231966, transparent 58%), #080807;
  padding: clamp(4rem, 8vh, 7rem) 1.5rem;
}
.book-back-cover > .content-shell { display: block; max-width: 70rem; }
.back-cover__inner { text-align: center; margin-inline: auto; max-width: 48rem; }
.back-cover__seal { display: block; width: clamp(120px, 20vh, 200px); height: auto; margin: 1rem auto 1.25rem; }
.book-back-cover h2 { max-width: none; font-family: var(--serif); font-size: clamp(2.2rem, 5.8vw, 5.2rem); font-weight: 400; line-height: 1.1; margin: 0; }
.back-cover__motto { color: #c6ad79; font-size: .72rem; letter-spacing: .24em; line-height: 1.8; text-transform: uppercase; margin: 1.6rem 0 2.5rem; }
.back-cover__links { display: flex; justify-content: center; align-items: center; flex-wrap: wrap; gap: 1.3rem 2.5rem; }
.back-cover__links .return-link { margin: 0; min-height: 44px; display: inline-flex; align-items: center; }
@media (max-height: 740px) and (min-width: 900px) {
  html.book-motion-ready .book-back-cover { padding-top: 2rem; padding-bottom: 3rem; }
  .back-cover__seal { width: 112px; margin: .4rem auto .8rem; }
  .book-back-cover h2 { font-size: 3.4rem; }
  .back-cover__motto { margin: 1rem 0 1.3rem; }
}
@media (prefers-reduced-motion: reduce) { .book-back-cover { scroll-margin-top: 6rem; } }