.chapter-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  z-index: 110;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.chapter-progress-bar--visible {
  opacity: 1;
}

.chapter-progress {
  position: fixed;
  inset-inline-end: clamp(16px, 3vw, 28px);
  bottom: clamp(16px, 3vw, 28px);
  z-index: 110;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 52px;
  padding: 8px 14px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--primary-dark);
  opacity: 0;
  transform: translateY(8px);
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.chapter-progress--visible {
  opacity: 1;
  transform: translateY(0);
}

.chapter-progress__value {
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

@media (prefers-reduced-motion: reduce) {
  .chapter-progress,
  .chapter-progress-bar {
    transition: none;
  }
}