/* JM24 Concept — Manim-frame look + fly / expand / regroup motion */
*, *::before, *::after { box-sizing: border-box; }

:root {
  /* JM25 shared/styles.py palette — quantity keeps its colour */
  --ink: #ffffff;
  --muted: #94a3b8;
  --gold-line: #e6c260;   /* title accent / GOLD captions */
  --sym-a: #4fc3f7;       /* COL_A — first base / group */
  --sym-b: #ffd54f;       /* COL_B — second base b */
  --sym-a2: #81c784;      /* COL_AB — second a-group / product role */
  --sym-y: #4fc3f7;       /* reuse COL_A for y */
  --pow: #ffd54f;         /* exponents — amber like COL_B */
  --note: #e6c260;        /* GOLD procedural captions */
  --strike: #e57373;      /* COL_REMOVE — cancel / danger */
  --box: #81c784;         /* SurroundingRectangle on final */
}

html, body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background: #0f172a;
  caret-color: transparent !important;
  -webkit-user-select: none !important;
  user-select: none !important;
  cursor: default;
}

.reveal,
.reveal * {
  caret-color: transparent !important;
  -webkit-user-select: none !important;
  user-select: none !important;
}

.reveal {
  width: 100%;
  height: 100%;
  background: #0f172a;
  color: var(--ink);
  font-family: "Times New Roman", Times, Georgia, serif;
}

.reveal .slides { text-align: center; }

/* Match JM25–27 / 30 / 32: title fixed at top, body in remaining frame */
.reveal .slides > section {
  /* Keep Reveal absolute stacking; title/stage position against this box */
  position: absolute !important;
  padding: 0 !important;
  width: 100% !important;
  height: 100% !important;
  min-height: 100% !important;
  max-height: 100% !important;
  display: flex !important;
  flex-direction: column !important;
  overflow: hidden !important;
  box-sizing: border-box !important;
  text-align: center;
}

.reveal h1,
.reveal h2,
.reveal .m-title {
  text-transform: none !important;
  letter-spacing: 0.01em !important;
}

/* Title + gold rule sit in one header so tall KaTeX never crosses the line */
.m-head {
  position: relative !important;
  flex: 0 0 auto;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  /* Manim title_bar: to_edge(UP, buff=0.5) ≈ 36px @720p; accent buff=0.14 */
  gap: 10px;
  padding: 36px 48px 12px;
  pointer-events: none;
}

.m-title {
  position: static !important;
  top: auto !important;
  left: auto !important;
  right: auto !important;
  z-index: 5;
  font-family: "Times New Roman", Times, Georgia, serif !important;
  /* Manim title_bar: font_size=52, color=INK */
  font-size: 52px !important;
  font-weight: normal !important;
  color: #f8fafc;
  margin: 0 !important;
  line-height: 1.25;
  text-align: center;
  pointer-events: none;
}

/* Manim title_bar: Write(title) + GrowFromCenter(accent) */
.m-head.title-enter .m-title {
  animation: titleWrite 0.85s ease both;
}
.m-head.title-enter .m-line {
  animation: titleGrowLine 0.7s cubic-bezier(0.22, 1.15, 0.36, 1) both;
  animation-delay: 0.12s;
}
@keyframes titleWrite {
  from { opacity: 0; clip-path: inset(0 100% 0 0); }
  to { opacity: 1; clip-path: inset(0 0 0 0); }
}
@keyframes titleGrowLine {
  from { opacity: 0; transform: scaleX(0.12); }
  to { opacity: 1; transform: scaleX(1); }
}
.m-line {
  transform-origin: center;
}

.m-title.m-title-eq {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  line-height: 1.2;
}
.m-title .m-why {
  display: block;
  line-height: 1.2;
}

/* Manim gold accent: stroke_width=3, width=title.width+0.6 */
.m-line {
  position: static !important;
  top: auto !important;
  left: auto !important;
  z-index: 5;
  width: 280px;
  height: 3px;
  margin: 0 !important;
  transform: scaleX(0);
  transform-origin: center;
  background: var(--gold-line);
  border-radius: 1px;
  pointer-events: none;
  transition: transform 0.55s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.reveal .slides > section.present .m-line {
  transform: scaleX(1);
}

/* Content stage fills the remaining frame under the header */
.m-stage {
  position: relative !important;
  top: auto !important;
  left: auto !important;
  right: auto !important;
  bottom: auto !important;
  z-index: 1;
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start !important;
  gap: 0;
  overflow: hidden;
  box-sizing: border-box;
  height: auto !important;
  padding: 10px 48px 28px;
}

/* Keep KaTeX a11y layer from painting over the slide */
.katex .katex-mathml {
  position: absolute !important;
  clip: rect(1px, 1px, 1px, 1px) !important;
  padding: 0 !important;
  border: 0 !important;
  height: 1px !important;
  width: 1px !important;
  overflow: hidden !important;
}

.m-sub {
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 26px;
  color: #e2e8f0;
  margin: 8px 0;
  line-height: 1.35;
  max-width: 1000px;
}

.m-sub.lead {
  font-size: 32px;
  color: #ffffff;
  font-weight: normal;
}
.m-sub.emphasis {
  font-size: 30px;
  color: var(--note);
}
.m-sub.quiet {
  font-size: 22px;
  color: var(--muted);
}
.m-logic {
  font-size: 28px;
  color: var(--pow);
  margin: 0 0.35em 0 0;
  flex-shrink: 0;
}
.logic-line {
  display: flex !important;
  align-items: baseline;
  justify-content: center;
  gap: 0.25em;
  width: 100%;
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}
.logic-line .m-logic {
  min-width: 1.1em;
}
.paren { color: #94a3b8; }

/* Yellow frame — roomy so it never clips powers / numerators; Example only */
.expand-framed,
.token.expand-framed,
.src.expand-framed,
.src-core.expand-framed,
.pv-grid .c.framed {
  outline: 2px solid var(--pow);
  outline-offset: 10px;
  border-radius: 6px;
  background: transparent;
  box-shadow: none;
}
.fly-ghost.expand-framed,
.fly-ghost .expand-framed {
  outline: none !important;
}

/* Core base only — outer power sits outside the yellow frame */
.example-row .src {
  display: inline-flex;
  flex-direction: row;
  flex-wrap: nowrap;
  align-items: center;
  gap: 0;
}
.example-row .src .src-core {
  display: inline-flex;
  flex-direction: row;
  flex-wrap: nowrap;
  align-items: center;
  padding: 6px 10px;
  border-radius: 6px;
  line-height: 1.15;
}
/* Outer power tucked tight against base (closer, not further) */
.example-row .src > .pow.outer,
.example-row .src > .pow,
.token.expand-src > .pow.outer,
.token > .pow.outer {
  margin-left: -0.28em !important;
  padding-left: 0 !important;
  top: -0.55em !important;
  font-size: 0.55em !important;
  line-height: 0 !important;
  vertical-align: super !important;
}

/* Stepped fraction build */
.frac-build {
  position: relative;
  width: 100%;
  min-height: 7.5em;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.frac-build .frac-phase {
  position: absolute !important;
  width: 0 !important;
  height: 0 !important;
  overflow: hidden !important;
  opacity: 0 !important;
  pointer-events: none !important;
}
.frac-build .num,
.frac-build .den {
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.35s ease;
}
.frac-build .frac-bar {
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.45s cubic-bezier(0.22, 0.61, 0.36, 1);
  min-width: 280px;
}
.frac-build .frac-stack.phase-bar .frac-bar,
.frac-build .frac-stack.phase-compact .frac-bar,
.frac-build .frac-stack.phase-num .frac-bar,
.frac-build .frac-stack.phase-expand .frac-bar,
.frac-build .frac-stack.phase-den .frac-bar,
.frac-build .frac-stack.phase-cancel .frac-bar,
.frac-build .frac-stack.phase-result .frac-bar {
  transform: scaleX(1);
}
.frac-build .frac-stack.phase-compact .num,
.frac-build .frac-stack.phase-compact .den,
.frac-build .frac-stack.phase-num .num,
.frac-build .frac-stack.phase-expand .num,
.frac-build .frac-stack.phase-expand .den,
.frac-build .frac-stack.phase-den .num,
.frac-build .frac-stack.phase-cancel .num,
.frac-build .frac-stack.phase-result .num {
  opacity: 1;
  visibility: visible;
}
.frac-build .frac-stack.phase-den .den,
.frac-build .frac-stack.phase-expand .den,
.frac-build .frac-stack.phase-cancel .den,
.frac-build .frac-stack.phase-result .den {
  opacity: 1;
  visibility: visible;
}
.gather-eq {
  opacity: 0;
  font-size: 36px;
  color: #fff;
  margin: 0;
  transition: opacity 0.35s ease;
}
.gather-eq.show { opacity: 1; }
/* = sits to the LEFT of the result (not above it) */
.gather-side {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  gap: 14px;
  min-height: 1.4em;
  margin-left: 18px;
}
.frac-stack.gathering,
.frac-stack.gathered {
  flex-direction: row;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px 12px;
}
.frac-stack .frac-body {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

/* Two methods side-by-side with a vertical divider; conclusion returns to center */
.two-method {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
}
.two-method .method-col {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  gap: 8px;
  padding: 8px 16px;
  min-width: 0;
}
.two-method .method-col:last-child {
  padding-top: 8px;
}
.two-method .method-col:last-child .neg-right-row {
  /* whole RHS moves up */
  margin-top: 0.55em;
  transform: translateY(-10px);
}
.method-col .neg-right-row .eq-lead {
  margin-left: 0.02em;
  margin-right: 0.15em;
  transform: translateY(2px);
}
.method-col .neg-right-result {
  font-size: 30px !important;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  transform: translateY(0);
}
.method-col .neg-right-row .frac-build {
  /* expansion fraction: up overall, then +2px down to ally with = */
  transform: translateY(-18px);
}
.neg-recip {
  display: inline-grid;
  grid-template-rows: 1fr auto 1fr;
  align-items: center;
  justify-items: center;
  vertical-align: middle;
  line-height: 1.05;
}
/* Keep y^{-2} as one glyph cluster (prevent cracked −2 during fly) */
.neg-left-result,
.neg-drag-left,
.neg-drag-right,
.neg-right-result {
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
}
.neg-left-result .pow,
.neg-drag-left .pow,
.neg-drag-right .pow,
.neg-right-result .pow {
  display: inline-block;
  white-space: nowrap;
  letter-spacing: 0;
}
.two-method .method-div {
  flex: 0 0 2px;
  width: 2px;
  align-self: stretch;
  background: linear-gradient(180deg, transparent, #64748b 12%, #64748b 88%, transparent);
  margin: 4px 4px;
}
.two-method + .story-band,
.story-band-conclude {
  width: 100%;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}
.cancel-caption {
  opacity: 0;
  margin-top: 8px;
  transition: opacity 0.35s ease;
  pointer-events: none;
}
.cancel-caption.show { opacity: 1; }
.muted-label { color: var(--muted); }

/* Sci equation stage — fixed seats, big RHS */
.sci-eq-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  width: 100%;
  max-width: 1040px;
  min-height: 9em;
}
.sci-lhs {
  font-size: 48px;
  line-height: 1.2;
  color: #fff;
  min-height: 1.3em;
}
.sci-rhs-live {
  width: 100%;
  min-height: 2.4em;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
.sci-jump-eq.sci-big {
  font-size: 44px;
  line-height: 1.25;
  gap: 0.12em;
  align-items: baseline;
}
.sci-jump-eq.sci-big .dp-live,
.sci-jump-eq.sci-big .dp {
  color: var(--strike);
  font-size: 1em;
  padding: 0 1px;
}
.sci-jump-eq {
  display: none;
  font-size: 34px;
  color: #fff;
  min-height: 1.4em;
}
.sci-jump-eq.is-on,
.sci-jump-eq.visible.is-on {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  animation: enterFade 0.35s ease both;
}
/* Keep unseen sci steps from collapsing the fixed seat oddly */
.reveal .m-stage .fragment.sci-jump-eq:not(.visible) {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  overflow: hidden !important;
  clip: rect(0,0,0,0) !important;
  opacity: 0 !important;
  pointer-events: none !important;
}

.pv-drag-box {
  position: fixed;
  z-index: 10000;
  pointer-events: none;
  box-sizing: border-box;
  border: 2px solid var(--pow);
  border-radius: 6px;
  background: rgba(15, 23, 42, 0.92);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 22px;
  transition: transform 0.55s cubic-bezier(0.22, 0.61, 0.36, 1), opacity 0.45s ease, border-color 0.45s ease, box-shadow 0.45s ease;
  box-shadow: 0 0 0 1px rgba(255, 213, 79, 0.35);
}
.pv-drag-box.fade-frame {
  border-color: transparent;
  box-shadow: none;
  opacity: 0.15;
}
.expand-term .term-times {
  opacity: 0;
  margin: 0 0.08em;
  transition: opacity 0.3s ease;
}
.expand-term.combining .term-times,
.expand-term.landed .term-times {
  opacity: 1;
}
.expand-term .term-digit { color: #fff; }
.expand-term .term-place { color: var(--note); }

.conv-subj {
  display: inline-block;
  min-width: 1.4em;
  color: var(--sym-y);
  font-weight: normal;
}
.conv-row {
  opacity: 0.35;
  transition: opacity 0.4s ease;
}
.conv-row.visible,
.conv-row.rhs-in {
  opacity: 1;
}

.m-sub.note-tone { color: var(--note); }
.m-sub.note-proc {
  /* Manim temporary note: INK @ ~0.75–0.8 opacity */
  color: rgba(255, 255, 255, 0.78);
  font-size: 24px;
}
.m-sub.note-sem {
  /* Semantic note — colour matches the concept being named */
  color: var(--sym-a2);
  font-size: 24px;
}
.m-sub.note-warn {
  color: var(--strike);
  font-size: 24px;
}

/* Manim Indicate — one-beat flash, not lasting */
@keyframes indicatePulse {
  0% { transform: scale(1); filter: brightness(1); }
  40% { transform: scale(1.35); filter: brightness(1.25); }
  100% { transform: scale(1); filter: brightness(1); }
}
.token.indicate,
.dp-live.indicate,
.src.indicate {
  animation: indicatePulse 0.7s ease;
  z-index: 3;
}

.m-eq {
  font-size: 40px;
  color: #f8fafc;
  margin: 8px 0;
  line-height: 1.4;
  max-width: 1100px;
}

.m-eq .katex,
.m-sub .katex,
.m-result .katex,
.m-title .katex {
  font-size: 1em !important;
}

.pow, .m-pow { color: var(--pow) !important; }
.m-hi { color: var(--note); }
.m-gold,
.calc-num {
  color: var(--pow) !important;
  font-size: 1em !important;
  font-style: normal;
  vertical-align: baseline !important;
  position: static !important;
  top: auto !important;
  line-height: inherit !important;
}

.sym-a, .token.sym-a, .digit.sym-a { color: var(--sym-a) !important; }
.sym-b, .token.sym-b, .digit.sym-b { color: var(--sym-b) !important; }
.sym-a2, .token.sym-a2 { color: var(--sym-a2) !important; }
.sym-y, .token.sym-y { color: var(--sym-y) !important; }

.m-result {
  font-size: 42px;
  color: var(--ink);
  margin-top: 14px;
  line-height: 1.35;
  max-width: 1000px;
}
/* Manim SurroundingRectangle(buff≈0.28) — lasting takeaway only */
.m-result.box-final,
.box-final {
  display: inline-block;
  padding: 0.28em 0.45em;
  border: 3px solid var(--box);
  border-radius: 4px;
  box-shadow: none;
  color: var(--ink);
}

.example-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 0.35em;
  font-size: 28px;
  margin: 6px 0 12px;
  color: #fff;
}
.example-row .src {
  display: inline-block;
  padding: 2px 5px;
  border-radius: 4px;
  transition: box-shadow 0.35s ease, opacity 0.35s ease;
  line-height: 1.2;
}
.example-row .src.is-source {
  /* framing uses .expand-framed only — avoid double yellow / layout shift */
  box-shadow: none;
}
.example-row .src.is-spent {
  /* Never permanently dim example terms after TransformFromCopy */
  opacity: 1;
}

/* Compact a/b as vertical fraction (LaTeX look) while keeping peelable HTML */
.mini-frac {
  display: inline-grid;
  grid-template-rows: 1fr auto 1fr;
  align-items: center;
  justify-items: center;
  vertical-align: middle;
  line-height: 1.05;
  margin: 0 0.08em;
  padding: 0 0.1em;
}
.mini-frac > .sym-a,
.mini-frac > .sym-b {
  line-height: 1;
}
.mini-frac .mini-bar {
  display: block;
  width: 100%;
  min-width: 0.85em;
  height: 2px;
  background: #fff;
  margin: 0;
  align-self: center;
}
/* Parentheses + mini-frac + outer power share one vertical center (the bar) */
.token:has(.mini-frac),
.example-row .src:has(.mini-frac) {
  display: inline-flex;
  flex-direction: row;
  flex-wrap: nowrap;
  align-items: center;
  vertical-align: middle;
  gap: 0;
  white-space: nowrap;
}
.token .paren,
.example-row .src .paren {
  align-self: center;
  line-height: 1;
  flex: 0 0 auto;
}
.token > .pow.outer,
.example-row .src > .pow.outer {
  flex: 0 0 auto;
  align-self: center;
  margin-left: -0.28em !important;
}
.eq-lead {
  margin-right: 0.35em;
  color: #fff;
}

/* Fraction bar = vertical center reference for same-row symbols */
.frac-align-row {
  display: inline-flex;
  flex-direction: row;
  flex-wrap: nowrap;
  align-items: center;
  justify-content: center;
  gap: 0.35em;
  max-width: 100%;
}
.frac-align-row .frac-build,
.frac-align-row .frac-stack,
.frac-align-row .frac-body {
  margin: 0;
  flex: 0 1 auto;
  min-width: 0;
}
.frac-align-row .op,
.frac-align-row .eq-lead,
.frac-align-row .neg-right-result {
  flex: 0 0 auto;
  align-self: center;
  line-height: 1;
}
.method-col .neg-right-row {
  width: auto;
  max-width: 100%;
  justify-content: center;
  gap: 0.18em; /* pull = and answer left toward the fraction */
}
.method-col .neg-right-row .frac-build {
  width: auto;
  display: inline-block;
  min-height: 0;
  transform: translateY(-18px);
}
.method-col .neg-right-row .frac-stack .token {
  font-size: 22px;
}
.method-col .neg-right-row .frac-bar {
  min-width: 120px;
}
.method-col .neg-right-row .eq-lead {
  margin-left: 0.02em;
  margin-right: 0.15em;
  transform: translateY(2px);
}
.method-col .neg-right-result {
  font-size: 30px !important;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
}
.method-col .neg-left-result {
  font-size: 30px !important;
}
.neg-left-result .sym-y,
.neg-right-result .sym-y,
.neg-drag-left .sym-y,
.neg-drag-right .sym-y {
  color: var(--sym-y) !important;
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 1em;
}
.neg-left-result .pow,
.neg-right-result .pow,
.neg-drag-left .pow,
.neg-drag-right .pow {
  color: var(--pow) !important;
  font-size: 0.62em !important;
  vertical-align: super;
}
.neg-recip {
  display: inline-grid;
  grid-template-rows: 1fr auto 1fr;
  align-items: center;
  justify-items: center;
  vertical-align: middle;
  line-height: 1.05;
}
.neg-recip .mini-bar {
  display: block;
  width: 100%;
  min-width: 1.1em;
  height: 2px;
  background: #fff;
  margin: 0;
}
.neg-recip-num {
  color: #fff;
  line-height: 1;
}
/* Result fractions keep base colors (never KaTeX white flash) */
.token.mini-frac.result-frac .sym-a,
.token.mini-frac.result-frac .sym-b {
  font-size: 1em;
}
.token.mini-frac.result-frac .pow {
  color: var(--pow) !important;
}

.compact-view {
  display: none;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 4px 6px;
}
.expand-view {
  display: none;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 4px 6px;
}
.frac-stack.phase-compact .compact-view { display: flex; }
.frac-stack.phase-compact .expand-view { display: none !important; }
.frac-stack.phase-num .compact-view,
.frac-stack.phase-expand .compact-view,
.frac-stack.phase-den .compact-view,
.frac-stack.phase-cancel .compact-view,
.frac-stack.phase-result .compact-view { display: none !important; }
.frac-stack.phase-num .expand-view,
.frac-stack.phase-expand .expand-view,
.frac-stack.phase-den .expand-view,
.frac-stack.phase-cancel .expand-view,
.frac-stack.phase-result .expand-view { display: flex; }

/* Only hide remainders after gather — keep cancelled ops/tokens visible until then */
.frac-stack.gathered .num .token.is-remaining,
.frac-stack.gathered .num .token.op.is-remaining,
.frac-stack.gathered .den .token.is-remaining,
.frac-stack.gathered .den .token.op.is-remaining {
  opacity: 0;
  transform: scale(0.6);
}
.frac-stack.gathered .num .token.cancelable,
.frac-stack.gathered .den .token.cancelable,
.frac-stack.gathered .num .token.op:not(.is-remaining),
.frac-stack.gathered .den .token.op:not(.is-remaining) {
  opacity: 0.35;
}

.cancel-result.morph-in {
  animation: morphIn 0.45s cubic-bezier(0.22, 1.15, 0.36, 1) both;
}
@keyframes morphIn {
  from { opacity: 0; transform: scale(0.72); }
  to { opacity: 1; transform: none; }
}

.neg-link-eq {
  display: none;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  gap: 0.45em;
  min-height: 1.6em;
  font-size: 40px;
}
.neg-link-eq.show {
  display: flex;
}
.neg-link-eq .fly-wait { opacity: 0; }
.neg-link-eq.linked .fly-wait,
.neg-link-eq.linked .fly-land { opacity: 1; }
.neg-link-step {
  position: absolute !important;
  width: 0 !important;
  height: 0 !important;
  overflow: hidden !important;
  opacity: 0 !important;
}

.story-stack.even-gap {
  gap: 14px;
}
.story-stack.even-gap .story-band {
  min-height: 2.5em;
}

.token-row,
.digit-row,
.work-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 4px 6px;
  margin: 10px 0;
  min-height: 1.45em;
}

.token,
.glyph {
  display: inline-block;
  position: relative;
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 30px;
  color: #ffffff;
  line-height: 1.25;
  padding: 0 1px;
  vertical-align: baseline;
}

.token.op,
.glyph.op { color: #cbd5e1; }
.token.hi { color: var(--note); }
.token.gold,
.glyph.gold { color: var(--pow); }
.token.rose { color: var(--strike); }

/* True LaTeX-like superscripts — descendant (not only direct child) so .src-core works */
.reveal .token .pow,
.reveal .src .pow,
.reveal .src-core .pow,
.reveal .example-row .pow,
.reveal .stage-pane .pow,
.reveal .m-eq .pow,
.fly-ghost .pow {
  color: var(--pow) !important;
  font-size: 0.58em !important;
  line-height: 0 !important;
  vertical-align: super !important;
  position: relative;
  top: -0.2em;
  font-style: normal;
}

/* Red cancel strike — one-by-one via .struck */
.token.cancelable .strike {
  position: absolute;
  left: -12%;
  right: -12%;
  top: 48%;
  height: 2.5px;
  background: var(--strike);
  transform: rotate(-28deg) scaleX(0);
  transform-origin: center;
  opacity: 0;
  pointer-events: none;
  z-index: 2;
  transition: transform 0.35s ease, opacity 0.25s ease;
}
.token.cancelable.struck {
  color: #94a3b8 !important;
}
.token.cancelable.struck .strike {
  opacity: 1;
  transform: rotate(-28deg) scaleX(1);
}
.frac-stack.cancelled .token.cancelable {
  color: #94a3b8 !important;
}
.frac-stack.cancelled .token.cancelable .strike {
  opacity: 1;
  transform: rotate(-28deg) scaleX(1);
}
.frac-stack .num .token.is-remaining,
.frac-stack.cancelled .num .token:not(.cancelable):not(.op) {
  color: var(--pow) !important;
  transition: color 0.35s ease, transform 0.65s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.token.gather-left {
  transform: translateX(-28px);
}
.token.gather-right {
  transform: translateX(28px);
}
.token.gather-mid {
  transform: scale(1.08);
}
.cancel-result {
  opacity: 0;
  transform: scale(0.9);
  transition: opacity 0.4s ease, transform 0.4s ease;
  font-size: 34px;
  margin: 0;
  color: var(--sym-a);
}
.cancel-result.show {
  opacity: 1;
  transform: none;
}
.cancel-result .pow { color: var(--pow) !important; }

.frac-stack {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  margin: 8px 0;
}
.frac-bar {
  width: 100%;
  min-width: 240px;
  height: 2px;
  background: #ffffff;
  margin: 2px 0;
}
.frac-stack .num,
.frac-stack .den {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 4px 6px;
}

.digit {
  min-width: 0.95em;
  text-align: center;
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 34px;
  color: #ffffff;
  padding: 0 2px;
  line-height: 1.15;
  position: relative;
}
.digit.dim { color: #94a3b8; }
.digit.focus { color: var(--note); }

.dp {
  color: var(--strike);
  font-size: 32px;
  padding: 0 2px;
  font-family: "Times New Roman", Times, Georgia, serif;
  position: relative;
  top: -1px;
}

.arc-svg {
  width: min(480px, 88%);
  height: 32px;
  margin: 2px auto 6px;
  display: block;
}
.arc-svg path {
  fill: none;
  stroke: var(--strike);
  stroke-width: 2.5;
  stroke-linecap: round;
}
.arc-svg text {
  fill: var(--strike);
  font-size: 16px;
  font-family: "Times New Roman", Times, Georgia, serif;
}

.pv-grid {
  display: inline-grid;
  gap: 0;
  margin: 10px auto;
  border: 1px solid rgba(148, 163, 184, 0.35);
  border-radius: 6px;
  overflow: hidden;
}
.pv-grid .c {
  padding: 8px 10px;
  border-right: 1px solid rgba(148, 163, 184, 0.22);
  border-bottom: 1px solid rgba(148, 163, 184, 0.22);
  font-family: "Times New Roman", Times, Georgia, serif;
  min-width: 48px;
  text-align: center;
}
.pv-grid .d { color: #fff; font-size: 28px; }
.pv-grid .p { color: var(--note); font-size: 22px; }
.pv-grid .p .pow { color: var(--pow); }
.pv-grid.denary { border-color: rgba(96, 165, 250, 0.5); }
.pv-grid.binary { border-color: rgba(244, 114, 182, 0.5); }
.pv-grid.binary .p { color: #f9a8d4; }

.expand-line {
  font-size: 24px;
  color: #e2e8f0;
  line-height: 1.45;
  max-width: 1040px;
  margin: 10px auto 0;
}
.expand-line .katex { font-size: 1em !important; }

.note {
  margin-top: 12px;
  font-size: 24px;
  color: #fde68a;
  max-width: 900px;
  line-height: 1.35;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px 40px;
  max-width: 980px;
  width: 100%;
  margin: 0 auto;
  text-align: left;
}
.col-h {
  font-size: 28px;
  margin: 0 0 8px;
  font-weight: normal;
}
.col-h.blue { color: #60a5fa; }
.col-h.pink { color: #f472b6; }
.two-col .m-sub { font-size: 24px; text-align: left; }

.laws-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 18px;
  max-width: 720px;
  width: 100%;
  margin: auto;
  text-align: center;
  font-size: 30px;
  color: #fff;
  flex: 1;
}
.laws-grid .full { width: 100%; text-align: center; }
.laws-grid .katex { font-size: 1em !important; }
.laws-grid .law-a .katex { color: #4fc3f7; }
.laws-grid .law-b .katex { color: #ffd54f; }
.laws-grid .law-a2 .katex { color: #81c784; }
.laws-grid .law-y .katex { color: #ce93d8; }
.laws-grid .law-pow .katex { color: #ffab91; }
/* Single centered column — equal x for every law */
.laws-grid .law-card {
  width: 100%;
  margin: 0;
  padding: 0;
  transform: none !important;
  text-align: center;
  min-height: 0;
  display: block;
}
.laws-grid .law-a2,
.laws-grid .law-y {
  min-height: 0;
  padding-top: 0;
  display: block;
}
.laws-grid .law-card .katex-display {
  margin: 0.12em 0 !important;
  text-align: center !important;
}
.laws-grid .law-card .katex-display > .katex {
  text-align: center !important;
  display: inline-block !important;
  margin: 0 !important;
}
.laws-grid .law-y .katex .mrel {
  margin-left: 0.14em !important;
  margin-right: 0.16em !important;
}
.reveal .fragment.law-card.visible {
  animation: enterFade 0.45s ease both;
}

.conv-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin: 8px 0;
  font-size: 26px;
}
.arrow { color: var(--pow); font-size: 1.1em; }

/* Ghost used by TransformFromCopy — no frame, no scale pop, keep one horizontal line */
.fly-ghost {
  position: fixed;
  z-index: 9999;
  pointer-events: none;
  margin: 0;
  padding: 0;
  outline: none !important;
  transition: transform 0.55s cubic-bezier(0.22, 0.61, 0.36, 1), opacity 0.2s ease;
  will-change: transform;
  filter: drop-shadow(0 4px 10px rgba(0, 0, 0, 0.45));
  transform: translate(0, 0) scale(1);
  box-sizing: border-box;
  display: inline-flex !important;
  flex-direction: row !important;
  flex-wrap: nowrap !important;
  align-items: center !important;
  white-space: nowrap !important;
  height: auto !important;
  width: auto !important;
}
.fly-ghost.flying {
  opacity: 0.95;
}
.fly-ghost .src-core,
.fly-ghost.fly-ghost-frac,
.fly-ghost.fly-ghost-frac .src-core {
  display: inline-flex !important;
  flex-direction: row !important;
  flex-wrap: nowrap !important;
  align-items: center !important;
  white-space: nowrap !important;
  outline: none !important;
  height: auto !important;
}
/* Keep vertical fraction during fly — never crack into two lines / (a—b) */
.fly-ghost .mini-frac,
.fly-ghost.fly-ghost-frac .mini-frac {
  display: inline-grid !important;
  grid-template-columns: 1fr !important;
  grid-template-rows: auto auto auto !important;
  align-items: center !important;
  justify-items: center !important;
  vertical-align: middle !important;
  line-height: 1.05 !important;
  white-space: normal !important;
  margin: 0 0.06em !important;
}
.fly-ghost .mini-bar,
.fly-ghost.fly-ghost-frac .mini-bar {
  display: block !important;
  width: 100% !important;
  min-width: 0.85em !important;
  height: 2px !important;
  background: #fff !important;
  margin: 1px 0 !important;
}
.fly-ghost .pow.outer,
.fly-ghost > .pow,
.fly-ghost.fly-ghost-frac > .pow,
.fly-ghost.fly-ghost-frac .pow.outer {
  margin-left: -0.28em !important;
  font-size: 0.55em !important;
  vertical-align: super !important;
  position: relative !important;
  top: -0.55em !important;
  flex: 0 0 auto !important;
}
.token.fly-wait,
.work-row.fly-wait > .token {
  opacity: 0 !important;
}
.token.fly-land,
.work-row .token.fly-land {
  animation: landFade 0.22s ease both;
}

@keyframes landFade {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Peel: real × stays in CSS seat; factors wait until power lands */
.work-fixed-frame .stage-pane .token.peel-factor-wait {
  opacity: 0 !important;
}
.work-fixed-frame .stage-pane .token.peel-times.peel-times-live {
  opacity: 1 !important;
}

/* PPT-style entrance — final transform always none (fixed seat) */
.reveal .fragment.m-sub,
.reveal .fragment.desc-enter,
.reveal .fragment.note,
.reveal .fragment.enter-wipe,
.reveal .fragment.enter-bounce,
.reveal .fragment.enter-fade,
.reveal .fragment.enter-pop {
  animation: none;
}
.reveal .fragment.m-sub.visible,
.reveal .fragment.enter-wipe.visible,
.reveal .fragment.desc-enter.visible {
  animation: enterWipe 0.65s ease both;
}
.reveal .fragment.m-result.visible,
.reveal .fragment.enter-bounce.visible,
.reveal .fragment.note.visible {
  animation: enterBounce 0.7s cubic-bezier(0.22, 1.25, 0.36, 1) both;
}
.reveal .fragment.m-eq.visible,
.reveal .fragment.enter-fade.visible {
  animation: enterFade 0.55s ease both;
}
.reveal .fragment.enter-pop.visible,
.reveal .fragment.work-slot.visible {
  animation: enterPop 0.55s cubic-bezier(0.22, 1.35, 0.36, 1) both;
}

@keyframes enterWipe {
  from { opacity: 0; clip-path: inset(0 100% 0 0); }
  to { opacity: 1; clip-path: inset(0 0 0 0); }
}
@keyframes enterBounce {
  0% { opacity: 0; transform: scale(0.94); }
  70% { opacity: 1; transform: scale(1.02); }
  100% { opacity: 1; transform: none; }
}
@keyframes enterFade {
  from { opacity: 0; }
  to { opacity: 1; }
}
@keyframes enterPop {
  from { opacity: 0; transform: scale(0.82); }
  to { opacity: 1; transform: none; }
}

/* Reserved bands — seats are fixed from the first frame; content only fades in */
.story-stack {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start !important;
  gap: 6px;
  width: 100%;
  max-width: 1000px;
  flex: 0 0 auto;
  margin: 0 auto;
}
.story-band {
  position: relative;
  width: 100%;
  min-height: 2.4em;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}
.story-band-example { min-height: 2.5em; }
.story-band-work { min-height: 3em; }
.story-band-frac { min-height: 5.8em; }
.story-band-count { min-height: 2.3em; }
.story-band-eq { min-height: 2.6em; }
.story-band-result { min-height: 2.8em; }
.story-band-note { min-height: 2.3em; }

.story-band > .example-row {
  margin: 0;
}

/* Peel-right ghost for power → factor expand (JS drives transform) */
.peel-ghost {
  position: fixed;
  z-index: 10000;
  pointer-events: none;
  color: var(--pow);
  font-family: "Times New Roman", Times, Georgia, serif;
  font-weight: normal;
  line-height: 1;
  will-change: transform, opacity;
  text-shadow: 0 2px 8px rgba(0,0,0,0.45);
  transition: opacity 0.2s ease;
}
.times-ghost {
  position: fixed;
  z-index: 10001;
  pointer-events: none;
  color: #cbd5e1;
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 30px;
  line-height: 1;
  transform: translate(-50%, -50%) scale(1);
  will-change: opacity;
  transition: opacity 0.12s linear;
}
.dp-ghost {
  position: fixed;
  z-index: 10000;
  pointer-events: none;
  color: var(--strike);
  font-family: "Times New Roman", Times, Georgia, serif;
  font-size: 34px;
  line-height: 1;
  will-change: transform;
}
.work-fixed-frame .stage-pane.is-measure {
  opacity: 0 !important;
  visibility: visible !important;
  pointer-events: none !important;
  z-index: -1;
}
/* Must beat .fragment.stage-pane:not(.visible){visibility:hidden} or × seat measures as 0 */
.reveal .m-stage .work-fixed-frame .fragment.stage-pane.is-measure {
  opacity: 0 !important;
  visibility: visible !important;
  pointer-events: none !important;
  z-index: 2;
  position: absolute !important;
  left: 0 !important;
  right: 0 !important;
  top: 50% !important;
  transform: translateY(-50%) !important;
  height: auto !important;
  overflow: visible !important;
}
.work-fixed-frame .stage-pane.is-measure-hide {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}
/* Peel seat: always overlay at frame center — ignore data-stack relative layout */
.work-fixed-frame .stage-pane.is-peel-seat,
.reveal .m-stage .work-fixed-frame .fragment.stage-pane.is-peel-seat,
.work-fixed-frame .stage-pane.is-measure.is-peel-seat,
.reveal .m-stage .work-fixed-frame .fragment.stage-pane.is-measure.is-peel-seat,
.work-fixed-frame[data-stack="1"] .stage-pane.is-peel-seat,
.reveal .m-stage .work-fixed-frame[data-stack="1"] .fragment.stage-pane.is-peel-seat,
.work-fixed-frame[data-stack="1"] .stage-pane.is-measure.is-peel-seat,
.reveal .m-stage .work-fixed-frame[data-stack="1"] .fragment.stage-pane.is-measure.is-peel-seat {
  position: absolute !important;
  left: 0 !important;
  right: 0 !important;
  top: 50% !important;
  transform: translateY(-50%) !important;
  height: auto !important;
  overflow: visible !important;
  z-index: 2;
}
.work-fixed-frame .stage-pane.is-measure.is-peel-seat,
.reveal .m-stage .work-fixed-frame .fragment.stage-pane.is-measure.is-peel-seat {
  opacity: 0 !important;
  visibility: visible !important;
}
.work-fixed-frame .stage-pane.is-active.is-peel-seat:not(.is-measure) {
  opacity: 1 !important;
  visibility: visible !important;
}
.work-fixed-frame[data-stack="1"] .stage-pane.is-measure,
.reveal .m-stage .work-fixed-frame[data-stack="1"] .fragment.stage-pane.is-measure {
  position: relative !important;
  height: auto !important;
  transform: none !important;
  left: auto !important;
  right: auto !important;
  top: auto !important;
}
/* Hide real × until peel ghost finishes — ghost sits at final seat */
.work-fixed-frame .stage-pane .peel-times.is-peel-pending {
  opacity: 0 !important;
}
.work-fixed-frame .stage-pane.is-active.peel-arrive {
  /* no transform — only a soft fade so the row never pops */
  animation: none;
  opacity: 1;
}
@keyframes peelArrive {
  from { opacity: 0; }
  to { opacity: 1; }
}
.work-fixed-frame .stage-pane.fade-out-step {
  animation: stepFadeOut 0.32s ease both;
}
.work-fixed-frame .stage-pane.fade-in-step {
  animation: stepFadeIn 0.38s ease both;
}
@keyframes stepFadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}
@keyframes stepFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Scientific jump equations */
.sci-jump {
  width: 100%;
  max-width: 980px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}
.dp-jump-row {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 2px;
  min-height: 2em;
  position: relative;
}
.dp-jump-row [data-dp-slot] {
  display: inline-block;
  min-width: 0.55em;
  height: 1.2em;
}

/* Aligned place-value grids */
.pv-stack {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
}
.pv-grid.aligned {
  display: grid;
  width: 100%;
  max-width: 1000px;
  gap: 0;
  margin: 0;
  box-sizing: border-box;
}
.pv-grid.aligned .c {
  min-width: 0;
  width: 100%;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 10px 6px;
}
.pv-pair {
  display: contents;
}
.pv-frame-wrap {
  position: relative;
}
.pv-cell.framed,
.pv-grid .c.framed,
[data-pv-pair].framed .c {
  box-shadow: inset 0 0 0 2px var(--pow);
  background: rgba(255, 213, 79, 0.12);
}
.pv-grid .c.dragged,
[data-pv-pair].dragged .c {
  opacity: 0.45;
}
.expand-build {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 4px 8px;
  margin-top: 16px;
  min-height: 2.4em;
  font-size: 26px;
  width: 100%;
}
.expand-term {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.3s ease, transform 0.3s ease;
  color: #fff;
}
.expand-term.awaiting { opacity: 0.15; }
.expand-term.landed {
  opacity: 1;
  transform: none;
  animation: landPop 0.3s ease both;
}
.expand-term .pow { color: var(--pow) !important; }
.expand-value {
  opacity: 0;
  color: var(--note);
  font-size: 28px;
  transition: opacity 0.35s ease;
}
.expand-value.show { opacity: 1; }

.conv-seq .conv-row {
  opacity: 1;
}
.conv-extra {
  display: inline-block;
  transition: transform 0.55s cubic-bezier(0.22, 0.61, 0.36, 1), opacity 0.4s ease;
}
.conv-extra.dragging {
  color: var(--sym-y);
  transform: translateY(36px) scale(1.05);
}
.conv-extra.spent {
  opacity: 0.35;
}

/* One Reveal step = whole row; glyphs still fade / fly independently */
.reveal .fragment {
  opacity: 0;
  visibility: hidden;
  transition: none !important;
}
.reveal .fragment.visible,
.reveal .fragment.current-fragment {
  opacity: 1;
  visibility: visible;
}

/* Critical: unseen fragments must NOT reserve layout space (was overlapping the fixed title) */
.reveal .m-stage .fragment:not(.visible) {
  position: absolute !important;
  width: 0 !important;
  height: 0 !important;
  margin: 0 !important;
  padding: 0 !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  border: 0 !important;
  opacity: 0 !important;
  pointer-events: none !important;
}

.reveal .fragment:not(.step-row):not(.step-block):not(.work-row):not(.m-sub):not(.desc-enter):not(.note):not(.m-eq):not(.m-result):not(.work-slot):not(.enter-wipe):not(.enter-bounce):not(.enter-fade):not(.enter-pop):not(.law-card):not(.sci-jump):not(.pv-expand):not(.cancel-seq):not(.conv-seq):not(.frac-phase):not(.conv-row) {
  animation: manimFadeIn 0.4s ease both;
}

.reveal .fragment.step-row .glyph,
.reveal .fragment.step-row .token,
.reveal .fragment.step-row .digit,
.reveal .fragment.step-row .dp,
.reveal .fragment.step-row .pv-token,
.reveal .fragment.step-block .glyph,
.reveal .fragment.step-block .token,
.reveal .fragment.step-block .digit,
.reveal .fragment.step-block .dp,
.reveal .fragment.step-block .pv-token,
.reveal .fragment.step-block .frac-bar,
.reveal .fragment.work-row .token,
.reveal .fragment.work-row .glyph {
  opacity: 0;
}

.reveal .fragment.step-row.visible .glyph,
.reveal .fragment.step-row.visible .token,
.reveal .fragment.step-row.visible .digit,
.reveal .fragment.step-row.visible .dp,
.reveal .fragment.step-row.visible .pv-token,
.reveal .fragment.step-block.visible .glyph,
.reveal .fragment.step-block.visible .token,
.reveal .fragment.step-block.visible .digit,
.reveal .fragment.step-block.visible .dp,
.reveal .fragment.step-block.visible .pv-token,
.reveal .fragment.step-block.visible .frac-bar {
  animation: manimFadeIn 0.36s ease both;
}

/* Work rows: drag-in from above (default when no JS fly-from) */
.reveal .fragment.work-row.visible .token:not(.fly-wait):not(.fly-land) {
  animation: dragDown 0.5s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}

@keyframes dragDown {
  from { opacity: 0; transform: translateY(-28px) scale(0.92); }
  to { opacity: 1; transform: none; }
}

@keyframes manimFadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

/* Regroup: tokens slide into sorted a…a · b…b order */
.reveal .fragment.regroup-row.visible .token {
  animation: regroupIn 0.55s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}
.reveal .fragment.regroup-row.visible .token:nth-child(1) { --dx: 72px; animation-delay: 0.00s; }
.reveal .fragment.regroup-row.visible .token:nth-child(2) { --dx: 40px; animation-delay: 0.04s; }
.reveal .fragment.regroup-row.visible .token:nth-child(3) { --dx: 8px; animation-delay: 0.08s; }
.reveal .fragment.regroup-row.visible .token:nth-child(4) { --dx: 0; animation-delay: 0.10s; }
.reveal .fragment.regroup-row.visible .token:nth-child(5) { --dx: -40px; animation-delay: 0.12s; }
.reveal .fragment.regroup-row.visible .token:nth-child(6) { --dx: -8px; animation-delay: 0.16s; }
.reveal .fragment.regroup-row.visible .token:nth-child(7) { --dx: 24px; animation-delay: 0.20s; }
.reveal .fragment.regroup-row.visible .token:nth-child(8) { --dx: -48px; animation-delay: 0.24s; }
.reveal .fragment.regroup-row.visible .token:nth-child(9) { --dx: -80px; animation-delay: 0.28s; }
.reveal .fragment.regroup-row.visible .token:nth-child(10) { --dx: -20px; animation-delay: 0.32s; }
.reveal .fragment.regroup-row.visible .token:nth-child(11) { --dx: -52px; animation-delay: 0.36s; }

@keyframes regroupIn {
  from { opacity: 0.35; transform: translateX(var(--dx, 40px)) scale(0.95); }
  to { opacity: 1; transform: none; }
}

/* Expand chain: only the current stage stays on screen (replace-in-place = TransformMatchingTex seat) */
.work-chain .work-row.chain-hidden {
  display: none !important;
}

/* Fixed-position stage — each .stage-step is one Manim next_slide() */
.work-fixed-frame {
  position: relative;
  width: 100%;
  min-height: 2.8em;
  display: flex;
  align-items: center;
  justify-content: center;
}
/* Entire expansion row is one centered block */
.work-fixed-frame .stage-pane {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  justify-content: center;
  gap: 4px 6px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-50%);
  pointer-events: none;
  white-space: nowrap;
}
.work-fixed-frame .stage-pane.is-active {
  opacity: 1;
  visibility: visible;
}
/* Fragments that are stage-steps stay in the fixed seat (do not collapse to 0×0) */
.reveal .m-stage .fragment.stage-pane:not(.visible) {
  position: absolute !important;
  width: auto !important;
  height: auto !important;
  left: 0;
  right: 0;
  overflow: visible !important;
  clip: auto !important;
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}
/* CRITICAL: past fragments keep .visible — only .is-active may paint (prevents stacking) */
.reveal .m-stage .fragment.stage-pane.visible:not(.is-active) {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}
.reveal .fragment.stage-pane.visible.is-active {
  opacity: 1 !important;
  visibility: visible !important;
}

/* Stacked coexistence: consecutive steps stay visible (Law 4–5) */
.work-fixed-frame[data-stack="1"] {
  position: relative;
  width: 100%;
  min-height: 2.8em;
  display: flex;
  align-items: center;
  justify-content: center;
}
/* Single pane: absolute center seat — same y before/after fly & peel (no pop) */
.work-fixed-frame[data-stack="1"]:not(.is-multi) .stage-pane,
.reveal .m-stage .work-fixed-frame[data-stack="1"]:not(.is-multi) .fragment.stage-pane {
  position: absolute !important;
  left: 0 !important;
  right: 0 !important;
  top: 50% !important;
  transform: translateY(-50%) !important;
  width: auto !important;
  height: auto !important;
  min-height: 0 !important;
  margin: 0 !important;
  overflow: visible !important;
}
.reveal .m-stage .work-fixed-frame[data-stack="1"]:not(.is-multi) .fragment.stage-pane:not(.visible) {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}
.reveal .m-stage .work-fixed-frame[data-stack="1"]:not(.is-multi) .fragment.stage-pane.visible.is-active {
  opacity: 1 !important;
  visibility: visible !important;
}
/* Two+ panes: true 上下 stack for compare */
.work-fixed-frame[data-stack="1"].is-multi {
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  gap: 8px;
  min-height: 0;
}
.work-fixed-frame[data-stack="1"].is-multi .stage-pane,
.reveal .m-stage .work-fixed-frame[data-stack="1"].is-multi .fragment.stage-pane {
  position: relative !important;
  left: auto !important;
  right: auto !important;
  top: auto !important;
  transform: none !important;
  width: 100% !important;
  height: auto !important;
}
.reveal .m-stage .work-fixed-frame[data-stack="1"].is-multi .fragment.stage-pane:not(.visible) {
  height: 0 !important;
  min-height: 0 !important;
  margin: 0 !important;
  padding: 0 !important;
  overflow: hidden !important;
  opacity: 0 !important;
  visibility: hidden !important;
}
.reveal .m-stage .work-fixed-frame[data-stack="1"].is-multi .fragment.stage-pane.visible.is-active,
.reveal .m-stage .work-fixed-frame[data-stack="1"].is-multi .fragment.stage-pane.visible.is-kept {
  opacity: 1 !important;
  visibility: visible !important;
  pointer-events: none;
}

.work-slot.fragment {
  width: 100%;
  max-width: 980px;
  margin: 8px auto;
}

.reveal .fragment.step-row.visible .glyph:nth-child(1),
.reveal .fragment.step-row.visible .token:nth-child(1),
.reveal .fragment.step-row.visible .digit:nth-child(1),
.reveal .fragment.step-block.visible .num .token:nth-child(1),
.reveal .fragment.step-block.visible .pv-token:nth-child(1),
.reveal .fragment.work-row.visible .token:nth-child(1) { animation-delay: 0.00s; }
.reveal .fragment.step-row.visible .glyph:nth-child(2),
.reveal .fragment.step-row.visible .token:nth-child(2),
.reveal .fragment.step-row.visible .digit:nth-child(2),
.reveal .fragment.step-row.visible .dp:nth-child(2),
.reveal .fragment.step-block.visible .num .token:nth-child(2),
.reveal .fragment.step-block.visible .pv-token:nth-child(2),
.reveal .fragment.work-row.visible .token:nth-child(2) { animation-delay: 0.06s; }
.reveal .fragment.step-row.visible .glyph:nth-child(3),
.reveal .fragment.step-row.visible .token:nth-child(3),
.reveal .fragment.step-row.visible .digit:nth-child(3),
.reveal .fragment.step-block.visible .num .token:nth-child(3),
.reveal .fragment.step-block.visible .pv-token:nth-child(3),
.reveal .fragment.work-row.visible .token:nth-child(3) { animation-delay: 0.12s; }
.reveal .fragment.step-row.visible .glyph:nth-child(4),
.reveal .fragment.step-row.visible .token:nth-child(4),
.reveal .fragment.step-row.visible .digit:nth-child(4),
.reveal .fragment.step-block.visible .num .token:nth-child(4),
.reveal .fragment.step-block.visible .pv-token:nth-child(4),
.reveal .fragment.work-row.visible .token:nth-child(4) { animation-delay: 0.18s; }
.reveal .fragment.step-row.visible .glyph:nth-child(5),
.reveal .fragment.step-row.visible .token:nth-child(5),
.reveal .fragment.step-row.visible .digit:nth-child(5),
.reveal .fragment.step-block.visible .num .token:nth-child(5),
.reveal .fragment.step-block.visible .pv-token:nth-child(5),
.reveal .fragment.work-row.visible .token:nth-child(5) { animation-delay: 0.24s; }
.reveal .fragment.step-row.visible .glyph:nth-child(6),
.reveal .fragment.step-row.visible .token:nth-child(6),
.reveal .fragment.step-row.visible .digit:nth-child(6),
.reveal .fragment.step-block.visible .num .token:nth-child(6),
.reveal .fragment.step-block.visible .frac-bar,
.reveal .fragment.step-block.visible .pv-token:nth-child(6),
.reveal .fragment.work-row.visible .token:nth-child(6) { animation-delay: 0.30s; }
.reveal .fragment.step-row.visible .glyph:nth-child(7),
.reveal .fragment.step-row.visible .token:nth-child(7),
.reveal .fragment.step-row.visible .digit:nth-child(7),
.reveal .fragment.step-block.visible .num .token:nth-child(7),
.reveal .fragment.step-block.visible .pv-token:nth-child(7),
.reveal .fragment.work-row.visible .token:nth-child(7) { animation-delay: 0.36s; }
.reveal .fragment.step-row.visible .glyph:nth-child(8),
.reveal .fragment.step-row.visible .token:nth-child(8),
.reveal .fragment.step-row.visible .digit:nth-child(8),
.reveal .fragment.step-block.visible .den .token:nth-child(1),
.reveal .fragment.step-block.visible .pv-token:nth-child(8),
.reveal .fragment.work-row.visible .token:nth-child(8) { animation-delay: 0.42s; }
.reveal .fragment.step-row.visible .glyph:nth-child(9),
.reveal .fragment.step-row.visible .token:nth-child(9),
.reveal .fragment.step-block.visible .den .token:nth-child(2),
.reveal .fragment.step-block.visible .pv-token:nth-child(9),
.reveal .fragment.work-row.visible .token:nth-child(9) { animation-delay: 0.48s; }
.reveal .fragment.step-row.visible .glyph:nth-child(10),
.reveal .fragment.step-row.visible .token:nth-child(10),
.reveal .fragment.step-block.visible .den .token:nth-child(3),
.reveal .fragment.step-block.visible .pv-token:nth-child(10),
.reveal .fragment.work-row.visible .token:nth-child(10) { animation-delay: 0.54s; }
.reveal .fragment.step-row.visible .glyph:nth-child(11),
.reveal .fragment.step-row.visible .token:nth-child(11),
.reveal .fragment.step-block.visible .den .token:nth-child(4),
.reveal .fragment.work-row.visible .token:nth-child(11) { animation-delay: 0.60s; }
.reveal .fragment.step-row.visible .glyph:nth-child(12),
.reveal .fragment.step-row.visible .token:nth-child(12),
.reveal .fragment.step-block.visible .den .token:nth-child(5),
.reveal .fragment.work-row.visible .token:nth-child(12) { animation-delay: 0.66s; }
.reveal .fragment.step-row.visible .token:nth-child(n+13),
.reveal .fragment.work-row.visible .token:nth-child(n+13) { animation-delay: 0.72s; }

/* Digit rows: drag-in feel */
.reveal .fragment.step-row.visible .digit,
.reveal .fragment.step-row.visible .dp {
  animation-name: dragDown;
  animation-duration: 0.48s;
}

/* Opening definition card: one short line of maths should read as the slide,
   not as a caption under a large empty stage. */
.hero-slide .m-head {
  padding: 28px 48px 8px;
}
.hero-slide .m-stage.fill-center {
  /* Sit the definition under the title, not in a dead-centre void. */
  justify-content: flex-start !important;
  padding: 36px 48px 32px;
}
.hero-slide .story-stack {
  gap: 20px;
}
.hero-slide .story-band,
.hero-slide .story-band-note,
.hero-slide .story-band-work {
  min-height: 0;
}
.hero-slide .m-sub {
  margin: 0;
}
.hero-slide .m-sub.lead {
  font-size: 42px;
}
.hero-slide .token-row.hero-eq {
  gap: 8px 14px;
  margin: 0;
}
.hero-slide .token-row.hero-eq .token {
  font-size: 64px;
}
.hero-slide .m-sub.note-proc {
  font-size: 34px;
}

.m-stage.fill-center {
  justify-content: center !important;
}
.two-col.fill {
  margin: auto;
  max-width: 1000px;
  gap: 36px 56px;
}
.two-col.fill .col-h { font-size: 36px; }
.two-col.fill .m-sub { font-size: 28px; }


/* Positive Indices: tight vertical rhythm — work sits under Example (not bottom-void);
   mid steps smaller than boxed rule (rule is the takeaway). */
body.loi-tight .m-head {
  padding: 14px 40px 10px;
  gap: 6px;
}
body.loi-tight .story-band-example {
  min-height: 2.1em;
  padding-top: 8px;
}
body.loi-tight .story-band-note {
  min-height: 1.5em;
  margin-top: 4px;
  padding-top: 4px;
}
body.loi-tight .story-band-result {
  min-height: 2.0em;
  margin-top: 2px;
}
body.loi-tight .slide-quot .story-band-note {
  margin-top: 10px;
}
body.loi-tight .slide-quot .work-fixed-frame .token.mini-frac.result-frac {
  font-size: 34px !important;
}
body.loi-tight .two-method {
  max-height: 42vh;
}
body.loi-tight .two-method .frac-stack .token {
  font-size: 20px;
}
body.loi-tight .neg-link-eq {
  font-size: 34px;
  min-height: 1.4em;
}
body.loi-tight .m-result.box-final {
  font-size: 40px;
  padding: 0.14em 0.36em;
}
body.loi-tight .m-title.m-title-eq { gap: 2px; }
body.loi-tight .m-stage {
  padding: 2px 36px 10px;
  justify-content: flex-start;
}
body.loi-tight .story-stack {
  gap: 4px;
}
body.loi-tight .story-band { min-height: 0; }
body.loi-tight .story-band-example {
  min-height: 2.15em;
  padding-top: 8px;
}
body.loi-tight .story-band-work { min-height: 2.1em; }
body.loi-tight .story-band-frac { min-height: 3.6em; }
body.loi-tight .story-band-count { min-height: 1.2em; }
body.loi-tight .story-band-note {
  min-height: 1.45em;
  margin-top: 6px;
  padding-top: 2px;
}
body.loi-tight .story-band-eq { min-height: 1.35em; }
body.loi-tight .story-band-result {
  min-height: 2.0em;
  margin-top: 4px;
}
body.loi-tight .work-fixed-frame { min-height: 2.1em; }
body.loi-tight .work-fixed-frame[data-stack="1"] { min-height: 0; }
body.loi-tight .frac-build { min-height: 3.8em; }
body.loi-tight .two-method .frac-build { min-height: 0; }
body.loi-tight .example-row { font-size: 34px; }
/* Mid working steps — smaller so boxed rule can dominate */
body.loi-tight .work-fixed-frame .token,
body.loi-tight .frac-stack .token {
  font-size: 34px;
}
body.loi-tight .two-method .frac-stack .token {
  font-size: 20px;
}
body.loi-tight .m-result.box-final {
  font-size: 42px;
  line-height: 1.15;
  padding: 0.16em 0.4em;
}
body.loi-tight .frac-bar { min-width: 180px; }
body.loi-tight .two-method .method-col {
  padding: 2px 12px;
  gap: 6px;
}
body.loi-tight .m-eq {
  font-size: 30px;
  margin: 0;
}
body.loi-tight .m-result,
body.loi-tight .example-row,
body.loi-tight .frac-stack,
body.loi-tight .token-row,
body.loi-tight .m-sub {
  margin: 0;
}
body.loi-tight .cancel-caption { margin-top: 4px; }
body.loi-tight .laws-grid {
  gap: 16px;
  flex: 0 0 auto;
  margin: 12px auto 0;
  font-size: 40px;
  max-width: 780px;
}
body.loi-tight .laws-grid .full.box-final {
  padding: 0.22em 0.55em;
}
body.loi-tight .m-stage.fill-center {
  justify-content: flex-start !important;
  padding-top: 18px;
}


/* Boxed rule is the takeaway — larger than mid derivation steps */
body.loi-tight .m-title.m-title-eq {
  font-size: 38px !important;
  line-height: 1.12;
}
body.loi-tight .m-result.box-final {
  font-size: 42px;
  line-height: 1.15;
  padding: 0.16em 0.4em;
}
body.loi-tight .slide-quot .m-head {
  padding-top: 12px;
  padding-bottom: 2px;
}
body.loi-tight .slide-quot .story-band-frac {
  min-height: 2.1em;
}
body.loi-tight .slide-quot .story-band-work,
body.loi-tight .slide-quot .work-fixed-frame {
  min-height: 2.1em;
}
body.loi-tight .slide-quot .work-fixed-frame .token {
  font-size: 34px;
}
body.loi-tight .slide-quot .m-result.box-final {
  font-size: 42px;
}
body.loi-tight .hero-slide .token-row.hero-eq .token {
  font-size: 58px;
}
body.loi-tight .hero-slide .m-sub.lead {
  font-size: 38px;
}

@media (max-width: 900px) {
  .m-title { font-size: 36px !important; }
  .m-sub, .note { font-size: 20px; }
  .m-sub.lead { font-size: 24px; }
  .m-eq, .m-result, .token, .digit { font-size: 24px; }
  .sci-jump-eq.sci-big { font-size: 28px; }
  .laws-grid { font-size: 26px; gap: 12px; max-width: 100%; }
  .hero-slide .m-sub.lead { font-size: 32px; }
  .hero-slide .token-row.hero-eq .token { font-size: 48px; }
  .hero-slide .m-sub.note-proc { font-size: 26px; }
  body.loi-tight .m-result.box-final { font-size: 32px; }
}