/* D2 local study: physical cues for the inline brochure only.
   Original artwork, navigation and the reading dialog remain untouched. */
#brochure .work-book-stage {
  perspective: 2400px;
  perspective-origin: 50% 46%;
}
#brochure .work-book-volume {
  /* Enlarge the object without shifting the original page's layout. */
  width: min(660px,64%);
  transform: scale(1.08) rotateX(4deg) rotateY(-8deg) rotateZ(-.8deg);
  transform-style: preserve-3d;
  box-shadow: 1px 3px 3px rgba(20,24,31,.10), 4px 12px 16px -10px rgba(20,24,31,.19);
}
/* Three thin folded sheets, rather than the block of a hardback book. */
#brochure .work-book-volume::before {
  inset: 2px -3px -3px 1px;
  border: 0;
  background: #fdfdfa;
  box-shadow: 0 1px 0 rgba(20,24,31,.16), 1px 0 0 rgba(20,24,31,.12);
}
#brochure .work-book-volume::after {
  inset: 4px -5px -5px 2px;
  border: 0;
  background: #f9f9f5;
  box-shadow: 0 1px 0 rgba(20,24,31,.15), 1px 0 0 rgba(20,24,31,.12);
}
#brochure .work-book-sheets {
  background: transparent;
  transform-style: preserve-3d;
}
#brochure .work-book-leaf { position:relative; transform-style:preserve-3d; }
#brochure .work-book-leaf img { position:relative; display:block; z-index:1; }
/* Narrow binding crease; no tint or crop applied to the cover artwork. */
#brochure .work-book-volume:not(.is-open) .work-book-leaf::before {
  content:"";
  position:absolute;
  z-index:2;
  top:0;
  bottom:0;
  left:0;
  width:11px;
  pointer-events:none;
  background:linear-gradient(to right,rgba(20,24,31,.17),rgba(255,255,255,.12) 18%,rgba(20,24,31,.035) 48%,transparent);
}
#brochure .work-book-volume.is-open {
  width:100%;
  transform:rotateX(5deg) rotateZ(-.35deg);
  box-shadow:none;
}
#brochure .work-book-volume.is-open::before,
#brochure .work-book-volume.is-open::after { content:none; }
#brochure .is-open .work-book-leaf {
  box-shadow:0 6px 10px -7px rgba(20,24,31,.22);
}
#brochure .is-open .work-book-leaf:first-child {
  transform-origin:100% 50%;
  transform:rotateY(-5deg);
}
#brochure .is-open .work-book-leaf:last-child {
  transform-origin:0 50%;
  transform:rotateY(5deg);
}
/* Exposed paper beneath each side follows that side's shallow angle. */
#brochure .is-open .work-book-leaf::after {
  content:"";
  position:absolute;
  inset:2px 0 -3px;
  z-index:0;
  pointer-events:none;
  background:#fdfdfa;
  box-shadow:0 1px 0 rgba(20,24,31,.17),0 3px 0 #f9f9f5,0 4px 0 rgba(20,24,31,.14);
}
#brochure .is-open .work-book-leaf:first-child::after { left:-2px; }
#brochure .is-open .work-book-leaf:last-child::after { right:-2px; }
/* Soft light falloff into the fold unifies the two original pages. */
#brochure .is-open .work-book-leaf::before {
  content:"";
  position:absolute;
  top:0;
  bottom:0;
  width:26px;
  z-index:2;
  pointer-events:none;
}
#brochure .is-open .work-book-leaf:first-child::before {
  right:0;
  background:linear-gradient(to left,rgba(20,24,31,.14),rgba(20,24,31,.025) 48%,transparent);
}
#brochure .is-open .work-book-leaf:last-child::before {
  left:0;
  background:linear-gradient(to right,rgba(20,24,31,.10),rgba(255,255,255,.13) 28%,transparent);
}
#brochure .is-open .work-book-sheets::after {
  left:50%;
  width:1px;
  background:rgba(20,24,31,.18);
  box-shadow:none;
  z-index:3;
}
@media(max-width:700px) {
  #brochure .work-book-stage { padding:14px 0 18px; perspective:1500px; }
  #brochure .work-book-volume {
    width:100%;
    transform:scale(.985) rotateX(3deg) rotateY(-7deg) rotateZ(-.6deg);
    box-shadow:1px 3px 3px rgba(20,24,31,.09),3px 9px 13px -9px rgba(20,24,31,.18);
  }
  #brochure .work-book-volume::before { inset:2px -2px -2px 1px; }
  #brochure .work-book-volume::after { inset:3px -4px -4px 2px; }
  #brochure .work-book-volume:not(.is-open) .work-book-leaf::before { width:8px; }
}