/* ============================================================
   NAV CSS — Chapter dots (right rail) + slide counter/arrows
   ============================================================ */

/* ── Chapter nav wrapper ──────────────────────────────────── */
.chapter-nav {
  position: fixed;
  right: 0;
  top: 0;
  height: 100dvh;
  width: var(--nav-w);
  z-index: var(--z-nav);
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

.chapter-nav__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  align-items: center;
  pointer-events: all;
}

/* ── Nav item ─────────────────────────────────────────────── */
.chapter-nav__item {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 20px;
  transition: all var(--dur-fast) var(--ease-out);
  cursor: pointer;
}

.chapter-nav__item:hover .chapter-nav__dot {
  transform: scale(1.8);
  background: var(--c-accent);
}

.chapter-nav__item.is-active .chapter-nav__dot {
  transform: scale(2.2);
  background: var(--c-accent);
  box-shadow: 0 0 8px var(--c-accent-glow);
}

/* ── Dot ──────────────────────────────────────────────────── */
.chapter-nav__dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.25);
  transition: transform var(--dur-base) var(--ease-out), background var(--dur-base) var(--ease-out);
  display: block;
  flex-shrink: 0;
}

body.scene-is-light .chapter-nav__dot {
  background: rgba(18, 18, 17, 0.22);
}

body.scene-is-light .chapter-nav__item.is-active .chapter-nav__dot,
body.scene-is-light .chapter-nav__item:hover .chapter-nav__dot {
  background: var(--c-accent);
}

/* ── Tooltip label ────────────────────────────────────────── */
.chapter-nav__label {
  position: absolute;
  right: 120%;
  top: 50%;
  transform: translateY(-50%) translateX(4px);
  white-space: nowrap;
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  letter-spacing: var(--ls-wide);
  color: var(--c-light-text);
  background: rgba(12, 12, 11, 0.88);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-fast), transform var(--dur-fast);
}

.chapter-nav__item:hover .chapter-nav__label {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
}

body.scene-is-light .chapter-nav__label {
  background: rgba(26, 26, 26, 0.9);
}

/* ── Mobile — bottom strip ────────────────────────────────── */
@media (max-width: 1024px) {
  .chapter-nav {
    position: fixed;
    bottom: 0;
    top: auto;
    right: 0;
    left: 0;
    width: 100%;
    height: 56px;
    background: rgba(12, 12, 11, 0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-top: 1px solid var(--c-rule-dark);
    align-items: center;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .chapter-nav::-webkit-scrollbar { display: none; }

  .chapter-nav__list {
    flex-direction: row;
    gap: var(--space-1);
    padding: 0 var(--space-4);
  }

  .chapter-nav__item {
    width: 28px;
    height: 32px;
  }

  .chapter-nav__label { display: none; }

  body.scene-is-light .chapter-nav {
    background: rgba(242, 240, 236, 0.95);
    border-top-color: var(--c-rule);
  }
}