.reader-shell {
  border: 1px solid var(--border);
  background: var(--panel);
  border-radius: 18px;
  overflow: hidden;
}

.reader-toolbar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 12px;
  align-items: center;
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  background: rgba(0,0,0,0.12);
}

.reader-status {
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  color: var(--muted);
  text-align: center;
  min-width: 170px;
}

.reader-stage {
  padding: 16px;
  display: grid;
  place-items: center;
}

.reader-help {
  padding: 12px 14px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.95rem;
}

.reader-help code {
  background: rgba(0,0,0,0.18);
  border: 1px solid var(--border);
  padding: 2px 6px;
  border-radius: 10px;
}

.book {
  position: relative;
  width: min(920px, 92vw);
  aspect-ratio: 3 / 4;
  perspective: 2200px;
  transform: translateZ(0);
}

.sheet {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transform-origin: left center;
  transition: transform 900ms cubic-bezier(.2,.7,.1,1);
  border-radius: 18px;
}

.sheet .face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  overflow: hidden;
  border-radius: 18px;
  border: 1px solid rgba(255,255,255,0.08);
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
  background: rgba(0,0,0,0.35);
}

.sheet .face img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.sheet .back {
  transform: rotateY(180deg);
}

.sheet.flipped {
  transform: rotateY(-180deg);
}

.sheet .page-badge {
  position: absolute;
  right: 10px;
  bottom: 10px;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 12px;
  letter-spacing: .02em;
  color: rgba(233, 238, 252, 0.9);
  background: rgba(0,0,0,0.35);
  border: 1px solid rgba(255,255,255,0.14);
}

@media (prefers-reduced-motion: reduce) {
  .sheet { transition: none; }
}