/* Scoped Stylesheet for Division, Factors & Multiples Lab */

:root {
  --lab-blue: #3b82f6;
  --lab-indigo: #6366f1;
  --lab-purple: #8b5cf6;
  --lab-pink: #ec4899;
  --lab-green: #10b981;
  --lab-emerald: #059669;
  --lab-yellow: #fbbf24;
  --lab-orange: #f59e0b;
  --lab-red: #ef4444;

  /* Theme Core Colors - Dark/Light Adaptable */
  --lab-bg-main: #f8fafc;
  --lab-bg-card: rgba(255, 255, 255, 0.94);
  --lab-border: rgba(36, 22, 111, 0.08);
  --lab-text-main: #0f172a;
  --lab-text-muted: #64748b;
  --lab-glass-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
  --board-bg: #ffffff;
  --board-grid: rgba(99, 102, 241, 0.03);
}

/* Dark Mode Overrides */
:root[data-theme="dark"] {
  --lab-bg-main: #0b0f19;
  --lab-bg-card: rgba(17, 24, 39, 0.85);
  --lab-border: rgba(255, 255, 255, 0.08);
  --lab-text-main: #f3f4f6;
  --lab-text-muted: #9ca3af;
  --lab-glass-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  --board-bg: #111827;
  --board-grid: rgba(255, 255, 255, 0.015);
}

/* Core Layouts styling */
body.lab-page {
  background-color: var(--lab-bg-main);
  color: var(--lab-text-main);
}

.lab-container {
  padding: 24px 16px 80px;
  max-width: 1200px;
  margin: 0 auto;
}

/* Breadcrumb Styling */
.breadcrumb-nav {
  margin-bottom: 16px;
  font-size: 0.9rem;
  font-weight: 700;
}
.breadcrumb-link {
  color: var(--lab-indigo);
  text-decoration: none;
  transition: opacity 0.2s;
}
.breadcrumb-link:hover {
  opacity: 0.8;
}
.breadcrumb-sep {
  margin: 0 8px;
  color: var(--lab-text-muted);
}
.breadcrumb-current {
  color: var(--lab-text-muted);
}

/* ================================================== */
/* LEARNING HUB (Landing Page)                        */
/* ================================================== */
.learning-hub-view {
  animation: fadeInSPA 0.4s ease-out;
}

.hub-hero {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(139, 92, 246, 0.04) 100%);
  border: 1.5px solid var(--lab-border);
  border-radius: 28px;
  padding: 40px 24px;
  margin-bottom: 32px;
  text-align: center;
  box-shadow: var(--lab-glass-shadow);
}
.hub-hero h1 {
  font-size: clamp(2rem, 5vw, 2.8rem);
  font-weight: 850;
  margin: 12px 0 8px;
  letter-spacing: -0.02em;
}
.hub-hero p {
  color: var(--lab-text-muted);
  font-size: 1.05rem;
  max-width: 700px;
  margin: 0 auto;
  line-height: 1.5;
}
.hub-section-title {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 20px;
  letter-spacing: -0.01em;
}

/* Learning Cards Grid */
.learning-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
}

.journey-card {
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  border-radius: 20px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
  box-shadow: var(--lab-glass-shadow);
  transition: transform 0.22s cubic-bezier(0.25, 1, 0.5, 1), box-shadow 0.22s, border-color 0.22s;
}

.journey-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 30px rgba(99, 102, 241, 0.08);
  border-color: rgba(99, 102, 241, 0.25);
}

/* Visual color progressions by Stage */
.journey-card.stage-cyan { border-left: 6px solid var(--lab-blue); }
.journey-card.stage-purple { border-left: 6px solid var(--lab-purple); }
.journey-card.stage-green { border-left: 6px solid var(--lab-green); }
.journey-card.stage-orange { border-left: 6px solid var(--lab-orange); }

.card-step-num {
  position: absolute;
  top: 10px;
  right: 18px;
  font-size: 3rem;
  font-weight: 900;
  opacity: 0.06;
  user-select: none;
  pointer-events: none;
}
.journey-card.stage-cyan .card-step-num { color: var(--lab-blue); }
.journey-card.stage-purple .card-step-num { color: var(--lab-purple); }
.journey-card.stage-green .card-step-num { color: var(--lab-green); }
.journey-card.stage-orange .card-step-num { color: var(--lab-orange); }

.card-main-content h3 {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}
.card-main-content p {
  font-size: 0.85rem;
  color: var(--lab-text-muted);
  line-height: 1.45;
  margin-bottom: 12px;
}
.card-preview-icon {
  margin-bottom: 14px;
  min-height: 32px;
  display: flex;
  align-items: center;
}

.card-action-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px dashed var(--lab-border);
  padding-top: 12px;
  margin-top: auto;
}
.card-status-badge {
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--lab-text-muted);
  background: rgba(0, 0, 0, 0.03);
  padding: 3px 8px;
  border-radius: 6px;
}
:root[data-theme="dark"] .card-status-badge {
  background: rgba(255, 255, 255, 0.03);
}
.journey-card.completed .card-status-badge {
  color: #fff;
  background: var(--lab-green);
}
.card-btn {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--lab-indigo);
  transition: color 0.15s;
}
.journey-card:hover .card-btn {
  color: var(--lab-purple);
}

/* ================================================== */
/* LESSON WORKSPACE VIEW                              */
/* ================================================== */
.lesson-workspace-view {
  animation: fadeInSPA 0.4s ease-out;
}

@keyframes fadeInSPA {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Progress Header Bar */
.lesson-progress-header {
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  border-radius: 18px;
  padding: 10px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
  box-shadow: var(--lab-glass-shadow);
}
.header-left {
  display: flex;
  align-items: center;
  gap: 16px;
}
.back-to-hub-btn {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--lab-text-muted);
  text-decoration: none;
  background: rgba(0,0,0,0.03);
  padding: 6px 12px;
  border-radius: 8px;
  border: 1px solid var(--lab-border);
  transition: all 0.15s;
}
:root[data-theme="dark"] .back-to-hub-btn {
  background: rgba(255,255,255,0.03);
}
.back-to-hub-btn:hover {
  color: var(--lab-indigo);
  background: rgba(99, 102, 241, 0.05);
}
.progress-step-lbl {
  font-size: 0.82rem;
  font-weight: 850;
}
.progress-dots-container {
  display: flex;
  gap: 4px;
}
.progress-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.08);
}
:root[data-theme="dark"] .progress-dot {
  background: rgba(255, 255, 255, 0.08);
}
.progress-dot.active {
  background: var(--lab-indigo);
  transform: scale(1.15);
}
.progress-dot.passed {
  background: var(--lab-green);
}
.header-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Lesson titles */
.lesson-title-area {
  margin-bottom: 20px;
  text-align: left;
}
.lesson-title-area h2 {
  font-size: 1.6rem;
  font-weight: 850;
  margin-bottom: 2px;
  letter-spacing: -0.02em;
}
.lesson-title-area p {
  font-size: 0.95rem;
  color: var(--lab-text-muted);
  margin: 0;
}

/* Workspace layout columns */
.lab-workspace {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 24px;
  margin-bottom: 24px;
}

/* LEFT COLUMN: Board Wrapper */
.workspace-main {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.interactive-board-wrapper {
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  border-radius: 24px;
  padding: 20px;
  box-shadow: var(--lab-glass-shadow);
  display: flex;
  flex-direction: column;
  gap: 14px;
  position: relative;
  overflow: hidden;
}

/* Board Instruction Header & Footer */
.board-instruction-header {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--lab-indigo);
  text-align: center;
  margin-bottom: 4px;
  letter-spacing: -0.01em;
}
.board-instruction-footer {
  background: rgba(99, 102, 241, 0.05);
  border: 1px solid rgba(99, 102, 241, 0.12);
  padding: 10px 16px;
  border-radius: 12px;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--lab-text-main);
  text-align: center;
  line-height: 1.4;
  margin-top: 4px;
}
:root[data-theme="dark"] .board-instruction-footer {
  background: rgba(99, 102, 241, 0.08);
  border-color: rgba(99, 102, 241, 0.2);
}

/* Theme Bar */
.token-theme-bar {
  display: flex;
  gap: 8px;
  align-items: center;
  z-index: 10;
}
.theme-label {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--lab-text-muted);
}
.token-theme-btn {
  font-family: inherit;
  font-size: 0.78rem;
  font-weight: 700;
  background: rgba(0, 0, 0, 0.03);
  border: 1px solid var(--lab-border);
  border-radius: 8px;
  padding: 4px 10px;
  cursor: pointer;
  color: var(--lab-text-main);
  transition: all 0.15s ease;
}
:root[data-theme="dark"] .token-theme-btn {
  background: rgba(255, 255, 255, 0.03);
}
.token-theme-btn:hover {
  background: rgba(99, 102, 241, 0.08);
}
.token-theme-btn.active {
  background: var(--lab-indigo);
  color: #fff;
  border-color: var(--lab-indigo);
}

/* Desktop: object choices are icon-only to keep the toolbar compact.
   Names remain available through title/aria-label and are restored on mobile. */
@media (min-width: 701px) {
  .token-theme-btn {
    width: 42px;
    height: 42px;
    min-width: 42px;
    padding: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
  }
  .token-theme-icon {
    font-size: 1.22rem;
    line-height: 1;
  }
  .token-theme-name {
    display: none;
  }
}

/* Interactive Board */
.interactive-board {
  background-color: var(--board-bg);
  background-image: 
    radial-gradient(var(--board-grid) 15%, transparent 15%),
    radial-gradient(var(--board-grid) 15%, transparent 15%);
  background-size: 20px 20px;
  background-position: 0 0, 10px 10px;
  border: 1.5px solid var(--lab-border);
  border-radius: 20px;
  height: 380px;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 2px 8px rgba(0,0,0,0.03);
  cursor: crosshair;
  touch-action: none;
}

/* Floating symbols watermark */
.board-watermark {
  position: absolute;
  bottom: 10px;
  right: 20px;
  font-size: 9rem;
  font-weight: 900;
  opacity: 0.025;
  user-select: none;
  pointer-events: none;
  font-family: 'Kanit', sans-serif;
  color: var(--lab-indigo);
}

/* SVG Lasso overlay */
.lasso-svg-layer {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 100;
}
.lasso-path {
  fill: rgba(99, 102, 241, 0.05);
  stroke: var(--lab-indigo);
  stroke-width: 2.5;
  stroke-dasharray: 4 2;
  transition: stroke 0.15s ease, fill 0.15s ease;
}
.lasso-path-closing {
  fill: none;
  stroke: rgba(99, 102, 241, 0.25);
  stroke-width: 1.5;
  stroke-dasharray: 3 3;
}

/* Organic Balloon-like Bubble Groups */
.static-group-path {
  stroke-width: 3.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  pointer-events: none;
  filter: drop-shadow(0 4px 10px rgba(99, 102, 241, 0.15));
  animation: bubbleWobble 6s infinite ease-in-out;
}

.group-path-0 { stroke: #06b6d4; fill: rgba(6, 182, 212, 0.04); filter: drop-shadow(0 4px 12px rgba(6, 182, 212, 0.25)); }
.group-path-1 { stroke: #8b5cf6; fill: rgba(139, 92, 246, 0.04); filter: drop-shadow(0 4px 12px rgba(139, 92, 246, 0.25)); }
.group-path-2 { stroke: #10b981; fill: rgba(16, 185, 129, 0.04); filter: drop-shadow(0 4px 12px rgba(16, 185, 129, 0.25)); }
.group-path-3 { stroke: #f59e0b; fill: rgba(245, 158, 11, 0.04); filter: drop-shadow(0 4px 12px rgba(245, 158, 11, 0.25)); }
.group-path-4 { stroke: #ec4899; fill: rgba(236, 72, 153, 0.04); filter: drop-shadow(0 4px 12px rgba(236, 72, 153, 0.25)); }
.group-path-5 { stroke: #3b82f6; fill: rgba(59, 130, 246, 0.04); filter: drop-shadow(0 4px 12px rgba(59, 130, 246, 0.25)); }

@keyframes bubbleWobble {
  0%, 100% { transform: scale(1) rotate(0deg); }
  50% { transform: scale(1.02) rotate(1deg); }
}

/* Tooltip */
.lasso-tooltip {
  position: absolute;
  background: var(--lab-text-main);
  color: var(--board-bg);
  padding: 6px 12px;
  font-size: 0.78rem;
  font-weight: 800;
  border-radius: 8px;
  pointer-events: none;
  z-index: 200;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  transform: translate(-50%, -100%) translateY(-10px);
  white-space: nowrap;
}

/* Tokens - Transitions on left/top removed for smooth custom drifting animations */
.token {
  position: absolute;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
  cursor: grab;
  z-index: 20;
  transition: transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275), box-shadow 0.2s ease, border-color 0.3s ease;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.08);
}
.token.dragging {
  cursor: grabbing;
  transform: scale(1.15) !important;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  z-index: 150;
  transition: none !important;
}
.token.grouped {
  cursor: default;
}
.token.inside-lasso {
  transform: scale(1.08);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3), 0 6px 16px rgba(99, 102, 241, 0.2);
}
.token.inside-lasso.green {
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.4), 0 6px 16px rgba(16, 185, 129, 0.2);
}
.token.inside-lasso.red {
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.4), 0 6px 16px rgba(239, 68, 68, 0.2);
}

/* Token Styles by Theme */
.token[data-theme="sphere"] {
  background: radial-gradient(circle at 30% 30%, #60a5fa, #1d4ed8);
  border: 1px solid rgba(255,255,255,0.25);
}
.token[data-theme="star"] {
  background: radial-gradient(circle at 30% 30%, #fef08a, #ca8a04);
  border: 1px solid rgba(255,255,255,0.25);
  clip-path: polygon(50% 0%, 61% 35%, 98% 35%, 68% 57%, 79% 91%, 50% 70%, 21% 91%, 32% 57%, 2% 35%, 39% 35%);
}
.token[data-theme="candy"] {
  background: radial-gradient(circle at 30% 30%, #f472b6, #db2777);
  border: 1px solid rgba(255,255,255,0.25);
}
.token[data-theme="crystal"] {
  background: radial-gradient(circle at 30% 30%, #34d399, #059669);
  border: 1px solid rgba(255,255,255,0.25);
  clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
}

.token.remainder {
  box-shadow: 0 0 14px rgba(245, 158, 11, 0.4);
  border: 2.5px solid var(--lab-orange) !important;
}

/* Floating Remainder Label */
.remainder-label {
  position: absolute;
  background: var(--lab-orange);
  color: #fff;
  padding: 4px 10px;
  font-size: 0.68rem;
  font-weight: 800;
  border-radius: 6px;
  z-index: 110;
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.3);
  transform: translate(-50%, -100%) translateY(-6px);
  pointer-events: none;
}

/* Lasso groups visual overlays */
.group-overlay-label {
  position: absolute;
  background: var(--lab-text-main);
  color: var(--board-bg);
  padding: 4px 8px;
  font-size: 0.65rem;
  font-weight: 800;
  border-radius: 6px;
  pointer-events: none;
  z-index: 90;
  transform: translate(-50%, -50%);
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
  opacity: 0.92;
}

/* Sharing Buckets (Mode B) */
.sharing-buckets-container {
  display: flex;
  justify-content: space-around;
  gap: 16px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--lab-border);
  z-index: 10;
}
.bucket {
  flex: 1;
  background: rgba(0,0,0,0.02);
  border: 2px dashed var(--lab-border);
  border-radius: 16px;
  min-height: 100px;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 8px;
  position: relative;
  transition: all 0.2s ease;
  box-sizing: border-box;
}
:root[data-theme="dark"] .bucket {
  background: rgba(255,255,255,0.01);
}
.bucket.hovered {
  border-color: var(--lab-indigo);
  background: rgba(99, 102, 241, 0.05);
}
.bucket.correct {
  border-color: var(--lab-green);
  background: rgba(16, 185, 129, 0.03);
}
.bucket-title {
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--lab-text-muted);
  margin-bottom: 4px;
}
.bucket-items {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  justify-content: center;
  align-items: center;
  width: 100%;
}
.bucket-token-dot {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--lab-indigo);
  border: 1px solid rgba(255,255,255,0.2);
}

/* LCM jumping tracks */
.lcm-tracks-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 12px;
  padding: 12px 0;
  border-top: 1px dashed var(--lab-border);
}
.lcm-track-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.track-label {
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--lab-text-muted);
  text-align: left;
}
.track-line-wrapper {
  position: relative;
  background: rgba(0,0,0,0.04);
  height: 48px;
  border-radius: 12px;
  border: 1.5px solid var(--lab-border);
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
}
:root[data-theme="dark"] .track-line-wrapper {
  background: rgba(255,255,255,0.02);
}
.track-line {
  position: relative;
  height: 100%;
  min-width: 600px;
  width: 100%;
}
.track-tick {
  position: absolute;
  top: 0;
  bottom: 0;
  border-left: 1px solid var(--lab-border);
  width: 40px;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 4px;
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--lab-text-muted);
  box-sizing: border-box;
}
.track-marker {
  position: absolute;
  top: 6px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 0.75rem;
  font-weight: 900;
  color: #fff;
  z-index: 10;
  transition: left 0.3s cubic-bezier(0.25, 1.25, 0.5, 1.25), transform 0.2s;
  transform: translateX(-50%);
}
.track-marker.color-a {
  background: var(--lab-blue);
  box-shadow: 0 0 10px rgba(59, 130, 246, 0.4);
}
.track-marker.color-b {
  background: var(--lab-purple);
  box-shadow: 0 0 10px rgba(139, 92, 246, 0.4);
}
.track-marker.jump {
  transform: translateX(-50%) translateY(-12px) scale(1.2);
}
.trail-dot {
  position: absolute;
  top: 14px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  transform: translateX(-50%);
  z-index: 5;
  animation: popTrail 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.trail-dot.color-a { background-color: var(--lab-blue); opacity: 0.6; }
.trail-dot.color-b { background-color: var(--lab-purple); opacity: 0.6; }
.trail-dot.common { 
  background-color: var(--lab-yellow); 
  width: 14px; 
  height: 14px; 
  top: 11px;
  box-shadow: 0 0 8px var(--lab-yellow);
  z-index: 6;
  opacity: 1;
}

@keyframes popTrail {
  0% { transform: translateX(-50%) scale(0); opacity: 0; }
  100% { transform: translateX(-50%) scale(1); }
}

.ripple-effect {
  position: absolute;
  top: 18px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 2px solid var(--lab-yellow);
  transform: translate(-50%, -50%);
  animation: runRipple 0.8s ease-out forwards;
  pointer-events: none;
}

@keyframes runRipple {
  0% { width: 0; height: 0; opacity: 1; }
  100% { width: 80px; height: 80px; opacity: 0; }
}

/* Toolbar Panel */
.board-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  padding: 10px 16px;
  border-radius: 16px;
  box-shadow: var(--lab-glass-shadow);
}
.toolbar-left {
  display: flex;
  gap: 8px;
}
.control-btn {
  font-family: inherit;
  font-weight: 700;
  font-size: 0.8rem;
  padding: 8px 14px;
  border-radius: 8px;
  border: 1px solid var(--lab-border);
  background: var(--board-bg);
  color: var(--lab-text-main);
  cursor: pointer;
  transition: all 0.15s ease;
}
.control-btn:hover {
  background: rgba(99, 102, 241, 0.05);
}
.control-btn.accent {
  background: var(--lab-indigo);
  color: #fff;
  border-color: var(--lab-indigo);
}
.control-btn.accent:hover {
  opacity: 0.9;
}
.sound-toggle-btn {
  background: transparent;
  border: none;
  font-size: 1.15rem;
  cursor: pointer;
  padding: 4px;
}

/* Compare Card */
.compare-card {
  margin-top: 12px;
  background: rgba(99, 102, 241, 0.03);
  border: 1.5px solid rgba(99, 102, 241, 0.12);
  border-radius: 16px;
  padding: 14px 18px;
  animation: popInPair 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  text-align: left;
}
:root[data-theme="dark"] .compare-card {
  background: rgba(99, 102, 241, 0.06);
  border-color: rgba(99, 102, 241, 0.2);
}
.compare-title {
  font-size: 0.88rem;
  font-weight: 850;
  color: var(--lab-indigo);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.compare-row {
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--lab-text-main);
  margin-bottom: 4px;
}
.compare-row:last-child {
  margin-bottom: 0;
}
.compare-highlight {
  color: var(--lab-indigo);
  font-weight: 800;
}

/* RIGHT COLUMN: Sidebar Panels */
.workspace-sidebar {
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.sidebar-panel {
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  border-radius: 20px;
  padding: 18px;
  box-shadow: var(--lab-glass-shadow);
}
.sidebar-panel.accent {
  border-color: rgba(99, 102, 241, 0.2);
  background: linear-gradient(180deg, var(--lab-bg-card) 0%, rgba(99, 102, 241, 0.015) 100%);
}
.panel-title {
  font-size: 0.9rem;
  font-weight: 800;
  color: var(--lab-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--lab-border);
  padding-bottom: 8px;
}

/* Sidebar settings controls elements */
.control-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 16px;
}
.control-group:last-child {
  margin-bottom: 0;
}
.control-label {
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--lab-text-main);
  display: flex;
  justify-content: space-between;
}
.control-value-lbl {
  color: var(--lab-indigo);
}
.input-slider {
  width: 100%;
  cursor: pointer;
}
.segmented-choices {
  display: flex;
  background: rgba(0,0,0,0.03);
  padding: 2px;
  border-radius: 10px;
  border: 1px solid var(--lab-border);
}
:root[data-theme="dark"] .segmented-choices {
  background: rgba(255,255,255,0.02);
}
.choice-btn {
  flex: 1;
  font-family: inherit;
  font-size: 0.76rem;
  font-weight: 700;
  background: transparent;
  border: none;
  color: var(--lab-text-muted);
  padding: 8px;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s;
}
.choice-btn:hover {
  color: var(--lab-text-main);
}
.choice-btn.active {
  background: var(--board-bg);
  color: var(--lab-text-main);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}

/* Divisor Buttons Grid */
.divisors-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}
.div-btn {
  font-family: inherit;
  font-weight: 800;
  font-size: 0.9rem;
  background: var(--board-bg);
  border: 1px solid var(--lab-border);
  color: var(--lab-text-main);
  border-radius: 10px;
  padding: 8px;
  cursor: pointer;
  transition: all 0.2s;
}
.div-btn:hover {
  border-color: var(--lab-indigo);
  transform: translateY(-1px);
}
.div-btn.correct-factor {
  background: var(--lab-green);
  color: #fff;
  border-color: var(--lab-green);
  box-shadow: 0 4px 10px rgba(16, 185, 129, 0.25);
}
.div-btn.incorrect-factor {
  background: rgba(239, 68, 68, 0.1);
  color: var(--lab-red);
  border-color: rgba(239, 68, 68, 0.2);
}

/* Factor Discovery Tab (Tab 3) */
.factor-machine-box {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.factor-pairing-visual {
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: rgba(0,0,0,0.02);
  border-radius: 12px;
  padding: 10px;
  min-height: 80px;
}
:root[data-theme="dark"] .factor-pairing-visual {
  background: rgba(255,255,255,0.01);
}
.pair-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 14px;
  font-size: 0.85rem;
  font-weight: 800;
  animation: popInPair 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes popInPair {
  0% { transform: scale(0.8); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}
.pair-num {
  padding: 2px 8px;
  background: var(--board-bg);
  border: 1px solid var(--lab-border);
  border-radius: 6px;
}
.pair-arrow {
  color: var(--lab-indigo);
}

/* GCD Lab */
.gcd-numbers-display {
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
.gcd-num-box {
  flex: 1;
  background: rgba(0,0,0,0.02);
  border-radius: 10px;
  padding: 6px;
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--lab-text-muted);
}
.gcd-num-box.color-a { border-left: 3px solid var(--lab-blue); }
.gcd-num-box.color-b { border-left: 3px solid var(--lab-purple); }
.gcd-num-box strong {
  font-size: 1.1rem;
  display: block;
  color: var(--lab-text-main);
  margin-top: 2px;
}

/* Monitor rows */
.realtime-monitor-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.monitor-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 700;
}
.monitor-row.header {
  border-bottom: 1.5px solid var(--lab-border);
  padding-bottom: 6px;
  margin-bottom: 2px;
  font-size: 0.72rem;
  color: var(--lab-text-muted);
  text-transform: uppercase;
}
.monitor-val {
  font-weight: 800;
  color: var(--lab-text-main);
}
.monitor-val.formula {
  font-family: 'Kanit', sans-serif;
  font-size: 1.05rem;
  color: var(--lab-indigo);
}

/* Accordion Fold */
.lab-knowledge-section {
  margin-bottom: 24px;
}
.accordion-card {
  background: var(--lab-bg-card);
  border: 1px solid var(--lab-border);
  border-radius: 20px;
  overflow: hidden;
  box-shadow: var(--lab-glass-shadow);
}
.accordion-header {
  width: 100%;
  background: transparent;
  border: none;
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  color: var(--lab-text-main);
}
.accordion-header h3 {
  font-size: 0.95rem;
  font-weight: 800;
  margin: 0;
}
.accordion-icon {
  font-size: 0.8rem;
  transition: transform 0.25s ease;
}
.accordion-header[aria-expanded="true"] .accordion-icon {
  transform: rotate(180deg);
}
.accordion-content {
  padding: 0 20px 20px;
  border-top: 1px solid var(--lab-border);
}
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding-top: 16px;
}
.knowledge-grid h4 {
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--lab-indigo);
  margin-bottom: 8px;
}
.knowledge-grid p {
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--lab-text-muted);
}

/* Challenges Panel */
.lab-challenge-section {
  margin-bottom: 24px;
}
.challenge-card {
  background: var(--lab-bg-card);
  border: 1px solid rgba(251, 191, 36, 0.3);
  border-radius: 20px;
  padding: 20px;
  box-shadow: var(--lab-glass-shadow);
  border-left: 5px solid var(--lab-yellow);
}
.challenge-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.challenge-badge {
  font-size: 0.8rem;
  font-weight: 900;
  color: #b45309;
}
.challenge-refresh {
  font-family: inherit;
  font-size: 0.72rem;
  font-weight: 800;
  background: transparent;
  border: none;
  color: var(--lab-text-muted);
  cursor: pointer;
  transition: color 0.15s;
}
.challenge-refresh:hover {
  color: var(--lab-indigo);
}
.challenge-question {
  font-size: 1rem;
  font-weight: 800;
  text-align: left;
  margin-bottom: 14px;
  color: var(--lab-text-main);
}
.challenge-answer-area {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.challenge-feedback {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 800;
  color: var(--lab-emerald);
  margin-top: 12px;
}

/* Journey Navigation Footer */
.lesson-navigation-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 24px;
  border-top: 1.5px solid var(--lab-border);
  padding-top: 20px;
}
.nav-btn-prev, .nav-btn-next {
  font-family: inherit;
  font-weight: 800;
  font-size: 0.95rem;
  padding: 12px 24px;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.25, 1, 0.5, 1);
  border: 1px solid var(--lab-border);
}
.nav-btn-prev {
  background: var(--board-bg);
  color: var(--lab-text-main);
}
.nav-btn-prev:hover {
  background: rgba(0,0,0,0.03);
}
:root[data-theme="dark"] .nav-btn-prev:hover {
  background: rgba(255,255,255,0.03);
}
.nav-btn-next {
  background: var(--lab-indigo);
  color: #fff;
  border-color: var(--lab-indigo);
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}
.nav-btn-next:hover {
  background: var(--lab-purple);
  border-color: var(--lab-purple);
  box-shadow: 0 6px 18px rgba(139, 92, 246, 0.4);
  transform: translateY(-1px);
}

/* Responsive viewports Breakpoints */
@media (max-width: 920px) {
  .lab-workspace {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

@media (max-width: 580px) {
  .lab-container {
    padding-top: 14px;
  }
  .hub-hero {
    padding: 24px 16px;
  }
  .learning-cards-grid {
    grid-template-columns: 1fr;
  }
  .lesson-progress-header {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
  }
  .header-left {
    justify-content: space-between;
  }
  .header-right {
    justify-content: space-around;
  }
  .interactive-board {
    height: 320px;
  }
  .token {
    width: 38px;
    height: 38px;
  }
  .board-toolbar {
    flex-direction: column;
    gap: 10px;
    align-items: stretch;
  }
  .toolbar-left {
    justify-content: space-around;
  }
  .knowledge-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  .lesson-navigation-footer {
    flex-direction: column;
    gap: 10px;
    align-items: stretch;
  }
}


/* ============================================================
   STEP 1 FOCUS PASS — "การหารคืออะไร?"
   Keep the first lesson simple: floating objects -> persistent groups.
   ============================================================ */
body[data-active-step="1"] .lab-workspace {
  grid-template-columns: minmax(0, 1.9fr) minmax(260px, .72fr);
  gap: 18px;
}

body[data-active-step="1"] .interactive-board {
  height: 470px;
  background-image:
    radial-gradient(circle at 20% 18%, rgba(59,130,246,.08), transparent 28%),
    radial-gradient(circle at 78% 76%, rgba(139,92,246,.07), transparent 30%),
    radial-gradient(var(--board-grid) 13%, transparent 13%),
    radial-gradient(var(--board-grid) 13%, transparent 13%);
  background-size: auto, auto, 20px 20px, 20px 20px;
  background-position: center, center, 0 0, 10px 10px;
}

body[data-active-step="1"] .lab-knowledge-section,
body[data-active-step="1"] .lab-challenge-section {
  display: none;
}

body[data-active-step="1"] .panel-title {
  text-transform: none;
  letter-spacing: 0;
  color: var(--lab-text-main);
  font-size: .92rem;
}

.step1-equation-card {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 10px;
  padding: 14px 10px;
  border-radius: 16px;
  border: 1px solid rgba(99,102,241,.24);
  background: linear-gradient(135deg, rgba(59,130,246,.08), rgba(139,92,246,.07));
  margin-bottom: 14px;
}
.step1-equation-number {
  font-size: 2.15rem;
  font-weight: 900;
  color: var(--lab-text-main);
}
.step1-equation-symbol {
  font-size: 1.7rem;
  font-weight: 900;
  color: var(--lab-indigo);
}
.step1-equation-question {
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--lab-orange);
}
.step1-meaning-card {
  display: grid;
  gap: 8px;
  padding: 12px 0 6px;
}
.step1-meaning-card > div {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .86rem;
}
.step1-meaning-card p {
  margin: 4px 0 0;
  font-size: .78rem;
  line-height: 1.55;
  color: var(--lab-text-muted);
}
.meaning-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex: 0 0 10px;
  box-shadow: 0 0 10px currentColor;
}
.meaning-dot.total { color: #3b82f6; background: currentColor; }
.meaning-dot.group { color: #10b981; background: currentColor; }
.step1-scatter-btn { width: 100%; margin-top: 8px; }

.instruction-focus {
  color: var(--lab-green);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

/* Bubble outlines are intentionally obvious and persistent. */
.static-group-path {
  stroke-width: 4;
  stroke-dasharray: none;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 7px rgba(99,102,241,.24));
}
.group-path-0 { fill: rgba(6,182,212,.085); }
.group-path-1 { fill: rgba(139,92,246,.085); }
.group-path-2 { fill: rgba(16,185,129,.085); }
.group-path-3 { fill: rgba(245,158,11,.085); }
.group-path-4 { fill: rgba(236,72,153,.085); }
.group-path-5 { fill: rgba(59,130,246,.085); }

.group-overlay-label {
  min-width: 72px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  transform: translate(-50%, -100%);
  padding: 5px 9px;
  border-radius: 999px;
  background: rgba(10,16,31,.88);
  color: #fff;
  border: 1px solid rgba(255,255,255,.16);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 120;
}
.group-overlay-label strong { font-size: .66rem; }
.group-overlay-label span { font-size: .58rem; opacity: .78; }

body[data-active-step="1"] .token.grouped {
  box-shadow: 0 0 0 2px rgba(255,255,255,.16), 0 8px 20px rgba(59,130,246,.18);
}

body[data-active-step="1"] .board-watermark {
  opacity: .018;
}

.division-discovery-result {
  display: grid;
  place-items: center;
  gap: 5px;
  padding: 4px 0;
}
.discovery-kicker {
  color: var(--lab-text-muted);
  font-size: .78rem;
}
.division-discovery-result > strong {
  font-size: 1.75rem;
  color: var(--lab-green);
}
.discovery-equation {
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--lab-indigo);
}
.discovery-meaning {
  max-width: 620px;
  font-size: .76rem;
  line-height: 1.5;
  color: var(--lab-text-muted);
}

body[data-active-step="1"] .interactive-board.division-complete {
  animation: boardSuccessPulse .8s ease-out;
}
body[data-active-step="1"] .interactive-board.division-complete .static-group-path {
  animation: bubbleSuccessPulse .75s ease-out;
}
@keyframes boardSuccessPulse {
  0% { box-shadow: inset 0 0 0 rgba(16,185,129,0), 0 0 0 rgba(16,185,129,0); }
  45% { box-shadow: inset 0 0 36px rgba(16,185,129,.10), 0 0 28px rgba(16,185,129,.15); }
  100% { box-shadow: inset 0 0 0 rgba(16,185,129,0), 0 0 0 rgba(16,185,129,0); }
}
@keyframes bubbleSuccessPulse {
  0%,100% { stroke-width: 4; opacity: 1; }
  45% { stroke-width: 6; opacity: .9; }
}

#actionAuto.is-running {
  opacity: .72;
  cursor: wait;
}

@media (max-width: 920px) {
  body[data-active-step="1"] .lab-workspace {
    grid-template-columns: 1fr;
  }
  body[data-active-step="1"] .workspace-sidebar {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }
}

@media (max-width: 580px) {
  body[data-active-step="1"] .interactive-board-wrapper {
    padding: 14px 10px;
    border-radius: 20px;
  }
  body[data-active-step="1"] .interactive-board {
    height: 390px;
    border-radius: 18px;
  }
  body[data-active-step="1"] .workspace-sidebar {
    grid-template-columns: 1fr;
  }
  body[data-active-step="1"] .token-theme-bar {
    overflow-x: auto;
    padding-bottom: 3px;
    scrollbar-width: none;
  }
  body[data-active-step="1"] .token-theme-bar::-webkit-scrollbar { display:none; }
  body[data-active-step="1"] .token-theme-btn { white-space: nowrap; }
  body[data-active-step="1"] .board-instruction-header { font-size: .95rem; }
  body[data-active-step="1"] .group-overlay-label { min-width: 62px; }
}

body[data-active-step="1"] .static-group-path {
  animation: none;
}


/* ============================================================
   STEP 1 V2 — compact draggable bubbles + practice/story modes
   ============================================================ */
body[data-active-step="1"] .lcm-tracks-container,
body[data-active-step="1"] .sharing-buckets-container {
  display: none !important;
}

body[data-active-step="1"] .interactive-board {
  height: 430px;
}

.step1-mode-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  padding: 5px;
  margin-bottom: 12px;
  border-radius: 14px;
  border: 1px solid var(--lab-border);
  background: rgba(99,102,241,.045);
}
.step1-mode-btn {
  min-height: 38px;
  padding: 7px 8px;
  border: 1px solid transparent;
  border-radius: 10px;
  background: transparent;
  color: var(--lab-text-muted);
  font-family: inherit;
  font-size: .72rem;
  font-weight: 800;
  cursor: pointer;
  transition: .18s ease;
}
.step1-mode-btn:hover {
  color: var(--lab-text-main);
  background: rgba(99,102,241,.08);
}
.step1-mode-btn.active {
  color: #fff;
  border-color: rgba(255,255,255,.14);
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
  box-shadow: 0 5px 16px rgba(79,70,229,.22);
}

.step1-practice-question {
  margin: 0 0 12px;
  padding: 12px;
  border-radius: 14px;
  border: 1px solid rgba(99,102,241,.18);
  background: rgba(99,102,241,.045);
}
.step1-practice-badge {
  display: inline-flex;
  margin-bottom: 6px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(99,102,241,.11);
  color: var(--lab-indigo);
  font-size: .66rem;
  font-weight: 900;
}
.step1-practice-question p {
  margin: 0 0 10px;
  color: var(--lab-text-main);
  font-size: .8rem;
  font-weight: 700;
  line-height: 1.48;
}
.step1-answer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}
.step1-answer-btn {
  min-height: 40px;
  border-radius: 10px;
  border: 1.5px solid var(--lab-border);
  background: rgba(255,255,255,.035);
  color: var(--lab-text-main);
  font: 900 .9rem/1 inherit;
  cursor: pointer;
  transition: .15s ease;
}
.step1-answer-btn:hover {
  transform: translateY(-1px);
  border-color: var(--lab-indigo);
}
.step1-answer-btn.correct {
  border-color: var(--lab-green);
  background: rgba(16,185,129,.11);
  color: var(--lab-green);
}
.step1-answer-btn.wrong {
  border-color: var(--lab-red);
  background: rgba(239,68,68,.09);
  color: var(--lab-red);
}
.step1-answer-feedback {
  margin-top: 8px;
  min-height: 20px;
  color: var(--lab-text-muted);
  font-size: .68rem;
  line-height: 1.4;
}
.step1-answer-feedback.correct { color: var(--lab-green); font-weight: 800; }
.step1-answer-feedback.wrong { color: var(--lab-red); font-weight: 800; }

.step1-control-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.step1-control-actions .control-btn {
  min-height: 40px;
  padding: 8px 9px;
  font-size: .7rem;
}
.step1-drag-hint {
  margin-top: 9px;
  padding: 8px 9px;
  border-radius: 10px;
  background: rgba(6,182,212,.06);
  color: var(--lab-text-muted);
  font-size: .66rem;
  line-height: 1.4;
}

body.step1-story-mode[data-active-step="1"] .token-theme-bar {
  opacity: .72;
}
body.step1-story-mode[data-active-step="1"] .token-theme-btn {
  pointer-events: none;
}

/* Grouped objects gather closer together after a successful lasso. */
body[data-active-step="1"] .static-group-path {
  stroke-width: 3.2;
}
body[data-active-step="1"] .token.grouped {
  cursor: grab;
  transform: scale(.92);
}
body[data-active-step="1"] .token.grouped:active,
body[data-active-step="1"] .group-overlay-label:active {
  cursor: grabbing;
}
body[data-active-step="1"] .group-overlay-label {
  pointer-events: auto;
  cursor: grab;
  touch-action: none;
  user-select: none;
}
body[data-active-step="1"] .group-overlay-label.dragging {
  transform: translate(-50%, -100%) scale(1.04);
}

/* Real-life / pictorial objects. Keep the same hit box for lasso geometry. */
.token[data-theme="apple"],
.token[data-theme="strawberry"],
.token[data-theme="car"],
.token[data-theme="doll"],
.token[data-theme="student"],
.token[data-theme="soccer"],
.token[data-theme="cookie"],
.token[data-theme="flower"] {
  background: transparent;
  border: 0;
  box-shadow: none;
  clip-path: none;
  font-size: 35px;
  line-height: 1;
  filter: drop-shadow(0 5px 7px rgba(0,0,0,.16));
}
.token[data-theme="car"] { font-size: 37px; }
.token[data-theme="student"] { font-size: 36px; }
.token[data-theme="doll"] { font-size: 36px; }
.token[data-theme="soccer"] { font-size: 34px; }

.interactive-board.is-dragging-bubble {
  cursor: grabbing !important;
}
.interactive-board.is-dragging-bubble .lasso-tooltip {
  display: none !important;
}

@media (max-width: 580px) {
  body[data-active-step="1"] .interactive-board {
    height: 370px;
  }
  .step1-mode-tabs {
    gap: 4px;
  }
  .step1-mode-btn {
    font-size: .66rem;
    padding-inline: 4px;
  }
  .step1-control-actions {
    grid-template-columns: 1fr;
  }
  .step1-answer-grid {
    gap: 5px;
  }
  .step1-answer-btn {
    min-height: 38px;
  }
}

body[data-active-step="1"] .token-theme-bar {
  flex-wrap: wrap;
}
body.step1-story-mode[data-active-step="1"] .token-theme-bar {
  display: none;
}
@media (max-width: 580px) {
  body[data-active-step="1"] .token-theme-bar {
    flex-wrap: nowrap;
  }
}


/* ============================================================
   STEP 1 — STABLE LASSO / POINTER GESTURES
   ============================================================ */
.interactive-board {
  touch-action: none !important;
  overscroll-behavior: contain;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  -webkit-user-drag: none;
}

.interactive-board *,
.interactive-board .token,
.interactive-board .group-overlay-label {
  -webkit-user-drag: none;
}

.lasso-tooltip {
  display: none !important;
}

.interactive-board.is-lasso-drawing {
  cursor: crosshair !important;
}

.interactive-board.is-lasso-drawing,
.interactive-board.is-dragging-bubble {
  touch-action: none !important;
}


/* STEP 1 practice/story: answer only after the learner finishes grouping. */
.step1-answer-grid.locked {
  opacity: .55;
}
.step1-answer-btn:disabled {
  cursor: not-allowed !important;
  filter: grayscale(.3);
  transform: none !important;
}
.step1-answer-grid.ready {
  opacity: 1;
}

/* Extra protection after switching Step-1 modes on touch devices. */
.interactive-board,
.interactive-board * {
  -webkit-user-select: none !important;
  user-select: none !important;
  -webkit-touch-callout: none !important;
}


/* STEP 1 final polish */
.step1-set-switch{display:grid;grid-template-columns:auto 1fr 1fr;align-items:center;gap:7px;margin:10px 0 4px;padding:7px;border:1px solid var(--lab-border);border-radius:13px;background:rgba(99,102,241,.045)}
.step1-set-switch>span{padding-inline:5px;color:var(--lab-text-muted);font-size:.72rem;font-weight:800}
.step1-set-btn{min-height:34px;border:1px solid transparent;border-radius:9px;background:transparent;color:var(--lab-text-muted);font:inherit;font-size:.75rem;font-weight:800;cursor:pointer}
.step1-set-btn.active{color:#fff;background:linear-gradient(135deg,var(--lab-indigo),#8b5cf6);box-shadow:0 5px 15px rgba(99,102,241,.2)}
.step1-set-note{margin:0 2px 10px;color:var(--lab-text-muted);font-size:.7rem;line-height:1.35}
.step1-equation-map{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:7px;width:min(100%,420px);margin:8px auto 4px}
.step1-equation-map>div{padding:7px 5px;border:1px solid rgba(99,102,241,.22);border-radius:10px;background:rgba(99,102,241,.06);display:grid;gap:1px}
.step1-equation-map strong{font-size:1.05rem;color:var(--lab-indigo)}
.step1-equation-map span{font-size:.63rem;color:var(--lab-text-muted);font-weight:800}
.division-discovery-result.compact{gap:3px}
.step1-gesture-cue{position:absolute;inset:0;z-index:180;pointer-events:none;display:grid;place-items:center;opacity:0;transition:opacity .28s ease;background:radial-gradient(circle at center,rgba(99,102,241,.1),transparent 45%)}
.step1-gesture-cue.show{opacity:1}.step1-gesture-cue.leave{opacity:0}
.step1-gesture-cue .gesture-ring{position:absolute;width:150px;height:100px;border:3px dashed rgba(99,102,241,.75);border-radius:50%;animation:step1GestureRing 1.4s ease-in-out infinite}
.step1-gesture-cue .gesture-hand{position:absolute;font-size:2rem;animation:step1GestureHand 1.4s ease-in-out infinite}
.step1-gesture-cue>span{transform:translateY(78px);padding:7px 12px;border-radius:999px;color:#fff;background:rgba(17,24,39,.84);font-size:.78rem;font-weight:800;box-shadow:0 8px 22px rgba(0,0,0,.16)}
@keyframes step1GestureRing{0%,100%{transform:scale(.88) rotate(-4deg);opacity:.45}50%{transform:scale(1) rotate(3deg);opacity:1}}
@keyframes step1GestureHand{0%,100%{transform:translate(-62px,24px) rotate(-18deg)}50%{transform:translate(58px,-24px) rotate(14deg)}}
body.step1-extended-set .interactive-board{height:430px}
@media(max-width:700px){.step1-set-switch{grid-template-columns:1fr 1fr}.step1-set-switch>span{grid-column:1/-1;text-align:left}.step1-equation-map{gap:5px}.step1-equation-map>div{padding:6px 3px}body.step1-extended-set .interactive-board{height:440px}}


/* ============================================================
   AUTO EXAMPLE — INTERACTION LOCK
   During a scripted demonstration the board belongs to the demo.
   Pointer/touch/hover cannot interrupt or move tokens/bubbles.
   ============================================================ */
body.auto-demo-running .interactive-board {
  pointer-events: none !important;
  touch-action: none !important;
  user-select: none !important;
  -webkit-user-select: none !important;
  cursor: wait !important;
}

body.auto-demo-running #contextualControls,
body.auto-demo-running .token-theme-btn,
body.auto-demo-running #actionUndo,
body.auto-demo-running #actionReset,
body.auto-demo-running #actionAuto {
  pointer-events: none !important;
}

body.auto-demo-running #actionUndo,
body.auto-demo-running #actionReset,
body.auto-demo-running #actionAuto {
  opacity: .55;
}

.interactive-board.auto-demo-locked::after {
  content: "กำลังสาธิต...";
  position: absolute;
  right: 14px;
  bottom: 12px;
  z-index: 50;
  padding: 7px 11px;
  border-radius: 999px;
  background: rgba(15, 23, 42, .76);
  border: 1px solid rgba(148, 163, 184, .22);
  color: rgba(255,255,255,.86);
  font-size: .72rem;
  font-weight: 700;
  pointer-events: none;
  backdrop-filter: blur(8px);
}

[data-theme="light"] .interactive-board.auto-demo-locked::after {
  background: rgba(255,255,255,.88);
  color: #475569;
  border-color: rgba(100,116,139,.2);
}


/* ============================================================
   MOBILE LESSON POLISH — minimal, focused, complete
   ============================================================ */
@media (max-width: 700px) {
  html,
  body.lab-page {
    width: 100%;
    max-width: 100%;
    overflow-x: clip !important;
  }

  body.lab-page *,
  body.lab-page *::before,
  body.lab-page *::after {
    box-sizing: border-box;
  }

  body.lab-page .page-shell,
  body.lab-page .container,
  body.lab-page .lab-container,
  body.lab-page .lesson-workspace-view,
  body.lab-page .lab-workspace,
  body.lab-page .workspace-main,
  body.lab-page .workspace-sidebar,
  body.lab-page .interactive-board-wrapper,
  body.lab-page .interactive-board,
  body.lab-page .sidebar-panel,
  body.lab-page .board-toolbar,
  body.lab-page .lesson-navigation-footer {
    min-width: 0 !important;
    width: 100% !important;
    max-width: 100% !important;
  }

  /* ---------- Global header: compact standard mobile pattern ---------- */
  .site-header .nav-wrap {
    min-height: 62px !important;
    padding: 7px 10px !important;
    gap: 7px !important;
    flex-wrap: nowrap !important;
    overflow: visible !important;
  }

  .site-header .brand {
    min-width: 0 !important;
    flex: 1 1 auto !important;
    gap: 8px !important;
    overflow: hidden !important;
  }

  .site-header .brand-logo {
    width: 42px !important;
    height: 42px !important;
    min-width: 42px !important;
    border-radius: 12px !important;
  }

  .site-header .brand > div {
    min-width: 0 !important;
  }

  .site-header .brand-title {
    font-size: .94rem !important;
    line-height: 1.1 !important;
    white-space: nowrap !important;
    overflow: hidden !important;
    text-overflow: ellipsis !important;
  }

  .site-header .brand-subtitle {
    font-size: .68rem !important;
    line-height: 1.15 !important;
    white-space: nowrap !important;
    overflow: hidden !important;
    text-overflow: ellipsis !important;
  }

  .site-header .main-nav {
    display: none;
  }

  .site-header .header-actions {
    margin-left: auto !important;
    flex: 0 0 auto !important;
    display: flex !important;
    align-items: center !important;
    gap: 6px !important;
  }

  .site-header .theme-toggle,
  .site-header .menu-toggle {
    width: 42px !important;
    height: 42px !important;
    min-width: 42px !important;
    padding: 0 !important;
    display: grid !important;
    place-items: center !important;
    border-radius: 13px !important;
    line-height: 1 !important;
  }

  .site-header .theme-toggle { order: 1 !important; }
  .site-header .member-nav { order: 2 !important; margin: 0 !important; }
  .site-header .menu-toggle { order: 3 !important; font-size: 1.35rem !important; }

  /* auth-client can inject either an anchor or button; keep it icon-sized on phone */
  .site-header .member-nav > a,
  .site-header .member-nav > button,
  .site-header .member-nav .auth-login-btn,
  .site-header .member-nav .profile-button {
    width: 42px !important;
    height: 42px !important;
    min-width: 42px !important;
    max-width: 42px !important;
    padding: 0 !important;
    border-radius: 50% !important;
    overflow: hidden !important;
    display: grid !important;
    place-items: center !important;
    font-size: 0 !important;
    white-space: nowrap !important;
  }

  .site-header .member-nav > a::before,
  .site-header .member-nav > button::before,
  .site-header .member-nav .auth-login-btn::before {
    content: "👤";
    font-size: 16px;
    line-height: 1;
  }

  /* ---------- Main page spacing ---------- */
  .lab-container {
    padding: 12px 10px 48px !important;
  }

  .lesson-progress-header {
    display: grid !important;
    grid-template-columns: auto 1fr auto !important;
    grid-template-areas:
      "back step actions"
      "dots dots dots" !important;
    gap: 7px 9px !important;
    align-items: center !important;
    padding: 8px !important;
    margin-bottom: 14px !important;
    border-radius: 15px !important;
  }

  .lesson-progress-header .header-left {
    display: contents !important;
  }

  .back-to-hub-btn {
    grid-area: back;
    min-height: 38px;
    padding: 7px 10px !important;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    white-space: nowrap;
    font-size: .72rem !important;
  }

  .progress-step-lbl {
    grid-area: step;
    justify-self: start;
    font-size: .76rem !important;
    white-space: nowrap;
  }

  .progress-dots-container {
    grid-area: dots;
    justify-content: center;
    gap: 4px !important;
    padding: 1px 0 2px;
  }

  .progress-dot {
    width: 6px !important;
    height: 6px !important;
  }

  .lesson-progress-header .header-right {
    grid-area: actions;
    display: flex !important;
    justify-content: flex-end !important;
    gap: 5px !important;
  }

  #labSoundToggle,
  #actionReset {
    width: 38px !important;
    height: 38px !important;
    min-width: 38px !important;
    padding: 0 !important;
    border-radius: 11px !important;
    display: grid !important;
    place-items: center !important;
  }

  #actionReset .reset-label { display: none !important; }
  #actionReset .reset-icon { font-size: 1.05rem; }

  .lesson-title-area {
    margin: 0 2px 12px !important;
  }

  .lesson-title-area h2 {
    font-size: 1.36rem !important;
    line-height: 1.2 !important;
    margin-bottom: 4px !important;
  }

  .lesson-title-area p {
    font-size: .8rem !important;
    line-height: 1.45 !important;
  }

  /* ---------- Focused mobile content flow ---------- */
  body.mobile-lesson-layout .lab-workspace,
  body[data-active-step="1"] .lab-workspace {
    display: block !important;
    margin-bottom: 14px !important;
  }

  body.mobile-lesson-layout .workspace-main {
    display: flex !important;
    flex-direction: column !important;
    gap: 10px !important;
  }

  body.mobile-lesson-layout .workspace-sidebar {
    display: none !important;
  }

  body.mobile-lesson-layout #sidebarControlsPanel {
    order: 1;
  }
  body.mobile-lesson-layout .interactive-board-wrapper {
    order: 2;
  }
  body.mobile-lesson-layout .board-toolbar {
    order: 3;
  }
  body.mobile-lesson-layout #sidebarMonitorPanel {
    order: 4;
  }

  /* Controls become a compact lesson strip, not a dashboard card. */
  body.mobile-lesson-layout #sidebarControlsPanel,
  body.mobile-lesson-layout #sidebarMonitorPanel {
    padding: 10px !important;
    border-radius: 16px !important;
    box-shadow: none !important;
  }

  body.mobile-lesson-layout #sidebarControlsPanel .panel-title,
  body.mobile-lesson-layout #sidebarMonitorPanel .panel-title {
    display: none !important;
  }

  .step1-mode-tabs {
    margin: 0 0 8px !important;
    padding: 4px !important;
    gap: 4px !important;
    border-radius: 12px !important;
  }

  .step1-mode-btn {
    min-height: 36px !important;
    padding: 5px 3px !important;
    font-size: .64rem !important;
    line-height: 1.2 !important;
  }

  .step1-set-switch {
    margin: 6px 0 !important;
    gap: 5px !important;
  }

  .step1-practice-question {
    padding: 9px !important;
    margin: 7px 0 0 !important;
    border-radius: 12px !important;
  }

  .step1-practice-question p {
    font-size: .73rem !important;
    margin-bottom: 8px !important;
  }

  .step1-answer-grid {
    gap: 5px !important;
  }

  .step1-answer-btn {
    min-height: 36px !important;
    font-size: .82rem !important;
  }

  .step1-control-actions,
  .step1-drag-hint {
    margin-top: 7px !important;
  }

  /* ---------- Board ---------- */
  body[data-active-step="1"] .interactive-board-wrapper {
    padding: 10px !important;
    gap: 9px !important;
    border-radius: 18px !important;
    overflow: hidden !important;
  }

  .board-instruction-header {
    margin: 0 !important;
    padding: 0 2px !important;
    font-size: .86rem !important;
    line-height: 1.38 !important;
    text-align: left !important;
  }

  .token-theme-bar {
    width: 100% !important;
    max-width: 100% !important;
    display: flex !important;
    flex-wrap: nowrap !important;
    overflow-x: auto !important;
    overflow-y: hidden !important;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    gap: 6px !important;
    padding: 1px 0 4px !important;
  }
  .token-theme-bar::-webkit-scrollbar { display: none; }

  .theme-label {
    position: sticky;
    left: 0;
    z-index: 2;
    flex: 0 0 auto;
    padding: 5px 5px 5px 0;
    background: var(--lab-bg-card);
    font-size: .7rem !important;
  }

  .token-theme-btn {
    flex: 0 0 auto !important;
    white-space: nowrap !important;
    padding: 5px 8px !important;
    font-size: .68rem !important;
    border-radius: 9px !important;
  }
  .token-theme-btn .token-theme-icon {
    margin-right: 3px;
  }
  .token-theme-btn .token-theme-name {
    display: inline;
  }

  body[data-active-step="1"] .interactive-board,
  body.step1-extended-set[data-active-step="1"] .interactive-board {
    width: 100% !important;
    height: clamp(350px, 56vh, 430px) !important;
    min-height: 350px !important;
    border-radius: 16px !important;
  }

  /* Keep 46px token geometry: lab.js uses a 23px center for lasso math. */
  .token {
    width: 46px !important;
    height: 46px !important;
  }

  .token[data-theme="apple"],
  .token[data-theme="strawberry"],
  .token[data-theme="car"],
  .token[data-theme="doll"],
  .token[data-theme="student"],
  .token[data-theme="soccer"],
  .token[data-theme="cookie"],
  .token[data-theme="flower"] {
    font-size: 31px !important;
  }

  .group-overlay-label {
    min-width: 54px !important;
    padding: 4px 7px !important;
  }

  .group-overlay-label strong { font-size: .59rem !important; }
  .group-overlay-label span { font-size: .52rem !important; }

  .board-instruction-footer {
    padding: 8px 9px !important;
    margin-top: 0 !important;
    border-radius: 10px !important;
    font-size: .7rem !important;
    line-height: 1.35 !important;
  }

  /* ---------- Board actions ---------- */
  .board-toolbar {
    padding: 7px !important;
    border-radius: 14px !important;
    box-shadow: none !important;
  }

  .toolbar-left {
    width: 100% !important;
    display: grid !important;
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr) !important;
    gap: 6px !important;
  }

  .toolbar-left .control-btn {
    min-width: 0 !important;
    min-height: 40px !important;
    padding: 7px 8px !important;
    font-size: .7rem !important;
    white-space: normal !important;
  }

  /* ---------- Compact realtime monitor ---------- */
  #sidebarMonitorPanel .realtime-monitor-grid {
    display: grid !important;
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 6px !important;
  }

  #sidebarMonitorPanel .monitor-row {
    min-width: 0;
    padding: 7px 8px;
    border-radius: 10px;
    background: rgba(99,102,241,.045);
    font-size: .68rem !important;
    gap: 6px;
  }

  #sidebarMonitorPanel .monitor-row.header {
    display: none !important;
  }

  #sidebarMonitorPanel .monitor-row:last-child {
    grid-column: 1 / -1;
  }

  #sidebarMonitorPanel .monitor-val,
  #sidebarMonitorPanel .monitor-val.formula {
    font-size: .74rem !important;
    text-align: right;
    overflow-wrap: anywhere;
  }

  /* ---------- Bottom navigation ---------- */
  .lesson-navigation-footer {
    display: grid !important;
    grid-template-columns: auto minmax(0, 1fr) !important;
    gap: 7px !important;
    margin-top: 16px !important;
  }

  .nav-btn-prev,
  .nav-btn-next {
    min-height: 44px !important;
    padding: 9px 12px !important;
    font-size: .72rem !important;
  }

  .nav-btn-next {
    width: 100% !important;
  }

  .site-footer {
    margin-top: 20px !important;
  }
}

@media (max-width: 430px) {
  .site-header .brand-subtitle { display: none !important; }
  .site-header .brand-title { font-size: .9rem !important; }
  .site-header .brand-logo { width: 40px !important; height: 40px !important; min-width: 40px !important; }
  .site-header .theme-toggle,
  .site-header .menu-toggle,
  .site-header .member-nav > a,
  .site-header .member-nav > button,
  .site-header .member-nav .auth-login-btn,
  .site-header .member-nav .profile-button {
    width: 40px !important;
    height: 40px !important;
    min-width: 40px !important;
    max-width: 40px !important;
  }
  .back-to-hub-btn .back-label { display: none !important; }
  .back-to-hub-btn { width: 38px !important; justify-content: center; padding: 0 !important; }
  .progress-step-lbl { font-size: .72rem !important; }
  body[data-active-step="1"] .interactive-board,
  body.step1-extended-set[data-active-step="1"] .interactive-board {
    height: 370px !important;
  }
}


/* ============================================================
   STEP 1 — MOBILE FINAL POLISH
   Keep problem + grouping board in one compact visual unit.
   ============================================================ */
@media (max-width: 700px) {
  /* The controls/question card is now physically inside the board wrapper. */
  body.mobile-lesson-layout .interactive-board-wrapper > #sidebarControlsPanel {
    order: -5;
    width: 100% !important;
    margin: 0 !important;
    padding: 0 0 7px !important;
    border: 0 !important;
    border-radius: 0 !important;
    background: transparent !important;
    box-shadow: none !important;
  }

  body.mobile-lesson-layout .interactive-board-wrapper > #sidebarControlsPanel .contextual-controls {
    display: grid;
    gap: 6px;
  }

  /* Remove duplicated/verbose helper copy on phone; the equation,
     board instruction and live monitor already explain the same thing. */
  body.mobile-lesson-layout .step1-set-note {
    display: none !important;
  }

  body.mobile-lesson-layout .step1-meaning-card {
    margin: 0 !important;
    padding: 7px 8px !important;
    display: grid !important;
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 4px 8px !important;
    border-radius: 11px !important;
  }

  body.mobile-lesson-layout .step1-meaning-card > div {
    min-width: 0;
    font-size: .67rem !important;
    line-height: 1.25 !important;
  }

  body.mobile-lesson-layout .step1-meaning-card p {
    grid-column: 1 / -1;
    margin: 1px 0 0 !important;
    font-size: .63rem !important;
    line-height: 1.32 !important;
  }

  /* Keep the mode + question selectors compact. */
  body.mobile-lesson-layout .step1-mode-tabs {
    margin: 0 !important;
  }

  body.mobile-lesson-layout .step1-set-switch {
    margin: 0 !important;
    padding: 4px !important;
    min-height: 34px;
  }

  body.mobile-lesson-layout .step1-set-switch > span {
    font-size: .64rem !important;
  }

  body.mobile-lesson-layout .step1-set-btn {
    min-height: 30px !important;
    font-size: .67rem !important;
  }

  body.mobile-lesson-layout .step1-equation-card {
    min-height: 58px !important;
    margin: 0 !important;
    padding: 7px 10px !important;
    border-radius: 12px !important;
    display: flex !important;
    align-items: center;
    justify-content: center;
    gap: 8px !important;
  }

  body.mobile-lesson-layout .step1-equation-number {
    font-size: 1.55rem !important;
  }

  body.mobile-lesson-layout .step1-equation-symbol,
  body.mobile-lesson-layout .step1-equation-question {
    font-size: 1.25rem !important;
  }

  /* Practice/story question stays compact enough to keep the board on-screen. */
  body.mobile-lesson-layout .step1-practice-question {
    margin: 0 !important;
    padding: 7px !important;
  }

  body.mobile-lesson-layout .step1-practice-question p {
    margin: 0 0 6px !important;
    font-size: .68rem !important;
    line-height: 1.3 !important;
  }

  body.mobile-lesson-layout .step1-answer-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr)) !important;
  }

  /* "ตัวอย่างใหม่ / โจทย์ใหม่" + "กระจายวัตถุใหม่" on one row. */
  body.mobile-lesson-layout .step1-control-actions {
    width: 100% !important;
    margin: 0 !important;
    display: grid !important;
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 6px !important;
  }

  body.mobile-lesson-layout .step1-control-actions .control-btn,
  body.mobile-lesson-layout .step1-scatter-btn {
    width: 100% !important;
    min-width: 0 !important;
    min-height: 38px !important;
    margin: 0 !important;
    padding: 6px 7px !important;
    font-size: .68rem !important;
    line-height: 1.2 !important;
    white-space: normal !important;
  }

  body.mobile-lesson-layout .step1-drag-hint {
    margin: 0 !important;
    padding: 6px 8px !important;
    font-size: .61rem !important;
    line-height: 1.3 !important;
  }

  /* One-line board instruction such as:
     "มีของ 16 ชิ้น • ลากวง กลุ่มละ 4 ชิ้น" */
  body[data-active-step="1"] .board-instruction-header {
    width: 100%;
    white-space: nowrap !important;
    overflow: hidden !important;
    text-overflow: ellipsis !important;
    text-align: center !important;
    font-size: clamp(.67rem, 2.7vw, .78rem) !important;
    line-height: 1.25 !important;
    padding: 1px 0 !important;
  }

  /* A slightly shorter board keeps the problem and grouping surface
     visible together without making 20–36 object examples unusable. */
  body[data-active-step="1"] .interactive-board,
  body.step1-extended-set[data-active-step="1"] .interactive-board {
    height: clamp(320px, 50vh, 390px) !important;
    min-height: 320px !important;
  }

  /* Footer: fill the phone frame properly, no clipped/offset content. */
  body.lab-page .site-footer {
    width: 100% !important;
    max-width: 100% !important;
    margin: 18px 0 0 !important;
    padding-left: 0 !important;
    padding-right: 0 !important;
    overflow: hidden !important;
  }

  body.lab-page .site-footer .container,
  body.lab-page .site-footer .footer-wrap {
    width: 100% !important;
    max-width: 100% !important;
    margin-left: 0 !important;
    margin-right: 0 !important;
    padding-left: 16px !important;
    padding-right: 16px !important;
    box-sizing: border-box !important;
  }

  body.lab-page .site-footer .footer-brand,
  body.lab-page .site-footer .footer-social {
    width: 100% !important;
    min-width: 0 !important;
  }

  body.lab-page .site-footer .social-links {
    width: 100% !important;
    display: flex !important;
    flex-wrap: wrap !important;
    gap: 8px !important;
  }
}

@media (max-width: 430px) {
  body.mobile-lesson-layout .step1-meaning-card p {
    display: none !important;
  }

  body[data-active-step="1"] .interactive-board,
  body.step1-extended-set[data-active-step="1"] .interactive-board {
    height: 330px !important;
    min-height: 330px !important;
  }

  body.mobile-lesson-layout .step1-control-actions .control-btn,
  body.mobile-lesson-layout .step1-scatter-btn {
    font-size: .64rem !important;
    padding-inline: 5px !important;
  }
}


/* Step 1: Auto is a teaching aid only in Explore.
   When hidden in Practice/Story, keep the toolbar compact and intentional. */
@media (max-width: 700px) {
  body[data-active-step="1"] .board-toolbar .toolbar-left {
    width: 100%;
  }

  body[data-active-step="1"] #actionAuto[style*="display: none"] + #actionUndo {
    width: 100%;
    max-width: 220px;
  }
}


/* ============================================================
   STEP 2 — TWO MEANINGS OF DIVISION
   Uses Step 1 as the visual/interaction reference.
   ============================================================ */
body[data-active-step="2"] .challenge-panel {
  display: none !important;
}

.step2-meaning-switch {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
}

.step2-interpret-btn {
  border: 1px solid var(--lab-border);
  border-radius: 15px;
  background: rgba(99,102,241,.04);
  color: var(--lab-text-main);
  padding: 12px;
  min-height: 100px;
  text-align: left;
  display: grid;
  gap: 5px;
  cursor: pointer;
  transition: .18s ease;
}

.step2-interpret-btn:hover {
  transform: translateY(-1px);
  border-color: color-mix(in srgb, var(--lab-indigo) 55%, var(--lab-border));
}

.step2-interpret-btn.active {
  border-color: var(--lab-indigo);
  background: color-mix(in srgb, var(--lab-indigo) 13%, transparent);
  box-shadow: 0 8px 24px rgba(99,102,241,.14);
}

.step2-interpret-tag {
  color: var(--lab-indigo);
  font-size: .72rem;
  font-weight: 900;
}

.step2-interpret-btn strong { font-size: .95rem; }
.step2-interpret-btn small {
  color: var(--lab-text-muted);
  line-height: 1.35;
}

.step2-explore-hint,
.step2-meaning-feedback,
.step2-answer-feedback {
  border-radius: 12px;
  padding: 9px 11px;
  font-size: .74rem;
  line-height: 1.45;
  background: color-mix(in srgb, var(--lab-blue) 8%, transparent);
  color: var(--lab-text-muted);
}

.step2-discovery-summary {
  border: 1px solid color-mix(in srgb, var(--lab-green) 45%, var(--lab-border));
  border-radius: 15px;
  padding: 12px;
  background: color-mix(in srgb, var(--lab-green) 8%, transparent);
  display: grid;
  gap: 9px;
}

.step2-summary-title {
  font-weight: 900;
  color: var(--lab-text-main);
}

.step2-summary-equation {
  text-align: center;
  font-size: 1.55rem;
  font-weight: 1000;
  color: var(--lab-indigo);
}

.step2-summary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.step2-summary-grid > div {
  border: 1px solid var(--lab-border);
  border-radius: 11px;
  padding: 9px;
  display: grid;
  gap: 4px;
}

.step2-summary-grid span {
  color: var(--lab-text-muted);
  font-size: .7rem;
}

.step2-summary-grid strong {
  color: var(--lab-text-main);
  font-size: .8rem;
}

.step2-practice-card {
  border: 1px solid var(--lab-border);
  border-radius: 15px;
  padding: 11px;
  display: grid;
  gap: 9px;
  background: rgba(99,102,241,.025);
}

.step2-prompt {
  margin: 0;
  color: var(--lab-text-main);
  line-height: 1.45;
  font-weight: 800;
  font-size: .82rem;
}

.step2-thinking-question {
  color: var(--lab-text-muted);
  font-size: .72rem;
  font-weight: 800;
}

.step2-meaning-answer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 7px;
}

.step2-meaning-answer-btn {
  min-height: 48px;
  border: 1px solid var(--lab-border);
  background: rgba(99,102,241,.025);
  color: var(--lab-text-main);
  border-radius: 12px;
  font: inherit;
  font-size: .76rem;
  font-weight: 900;
  cursor: pointer;
}

.step2-meaning-answer-btn.correct {
  border-color: var(--lab-green);
  background: color-mix(in srgb, var(--lab-green) 12%, transparent);
}

.step2-meaning-answer-btn.wrong {
  border-color: var(--lab-red);
  background: color-mix(in srgb, var(--lab-red) 10%, transparent);
}

.step2-meaning-feedback.correct,
.step2-answer-feedback.correct {
  color: var(--lab-green);
  background: color-mix(in srgb, var(--lab-green) 8%, transparent);
}

.step2-meaning-feedback.wrong,
.step2-answer-feedback.wrong {
  color: var(--lab-red);
  background: color-mix(in srgb, var(--lab-red) 7%, transparent);
}

.step2-answer-stage {
  display: grid;
  gap: 7px;
  padding-top: 4px;
  border-top: 1px dashed var(--lab-border);
}

.step2-answer-stage.locked { opacity: .58; }

.sharing-buckets-container:not(.hidden) { display: grid; }

body[data-active-step="2"] .sharing-buckets-container {
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 9px;
  margin-top: 10px;
  padding: 10px 0 0;
}

body[data-active-step="2"] .bucket {
  min-height: 104px;
  border-radius: 20px;
  border-width: 2px;
  border-style: solid;
  background:
    radial-gradient(circle at 50% 120%, rgba(99,102,241,.09), transparent 60%),
    rgba(99,102,241,.025);
}

body[data-active-step="2"] .bucket.hovered {
  transform: translateY(-2px) scale(1.01);
  border-color: var(--lab-indigo);
}

body[data-active-step="2"] .bucket.correct {
  border-color: var(--lab-green);
  background: color-mix(in srgb, var(--lab-green) 7%, transparent);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--lab-green) 20%, transparent);
}

body[data-active-step="2"] .bucket-title {
  width: 100%;
  display: flex;
  justify-content: space-between;
  gap: 6px;
  color: var(--lab-text-main);
}

.bucket-count {
  color: var(--lab-indigo);
  font-weight: 900;
}

.bucket-items {
  min-height: 50px;
  align-content: center;
}

.bucket-token-mini {
  width: 27px;
  height: 27px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  font-size: 21px;
  line-height: 1;
  flex: 0 0 27px;
}

.bucket-token-mini[data-theme="sphere"] {
  background: radial-gradient(circle at 32% 28%, #93c5fd 0 14%, #3b82f6 38%, #1d4ed8 100%);
  box-shadow: inset -3px -4px 8px rgba(0,0,0,.16);
}

.bucket-token-mini[data-theme="star"] {
  background: #fbbf24;
  clip-path: polygon(50% 0%,61% 34%,98% 35%,68% 56%,79% 93%,50% 71%,21% 93%,32% 56%,2% 35%,39% 34%);
  border-radius: 0;
}

.bucket-token-mini[data-theme="candy"] {
  background: linear-gradient(135deg,#fb7185,#e11d48);
}

.bucket-token-mini[data-theme="crystal"] {
  background: linear-gradient(145deg,#67e8f9,#3b82f6 55%,#8b5cf6);
  clip-path: polygon(50% 0,90% 30%,72% 100%,28% 100%,10% 30%);
  border-radius: 0;
}

.monitor-emphasis {
  margin-top: 7px;
  padding-top: 7px;
  border-top: 1px dashed var(--lab-border);
}

.step2-monitor-compare { margin-top: 10px; }

@media (max-width: 700px) {
  body[data-active-step="2"] .interactive-board-wrapper > #sidebarControlsPanel {
    order: -5;
    width: 100% !important;
    margin: 0 !important;
    padding: 0 0 7px !important;
    border: 0 !important;
    border-radius: 0 !important;
    background: transparent !important;
    box-shadow: none !important;
  }

  body[data-active-step="2"] .step2-meaning-switch { gap: 6px; }

  body[data-active-step="2"] .step2-interpret-btn {
    min-height: 78px;
    padding: 9px;
    border-radius: 12px;
  }

  body[data-active-step="2"] .step2-interpret-btn strong { font-size: .77rem; }
  body[data-active-step="2"] .step2-interpret-btn small { font-size: .61rem; }

  body[data-active-step="2"] .step2-practice-card {
    padding: 8px;
    gap: 7px;
  }

  body[data-active-step="2"] .step2-prompt { font-size: .7rem; }

  body[data-active-step="2"] .step2-meaning-answer-btn {
    min-height: 41px;
    font-size: .67rem;
  }

  body[data-active-step="2"] .sharing-buckets-container {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 7px;
  }

  body[data-active-step="2"] .bucket {
    min-height: 82px;
    padding: 7px;
    border-radius: 15px;
  }

  body[data-active-step="2"] .bucket-title { font-size: .62rem; }

  body[data-active-step="2"] .bucket-token-mini {
    width: 22px;
    height: 22px;
    flex-basis: 22px;
    font-size: 17px;
  }

  body[data-active-step="2"] .step2-summary-grid { grid-template-columns: 1fr; }

  body[data-active-step="2"] .interactive-board {
    height: clamp(300px, 45vh, 350px) !important;
    min-height: 300px !important;
  }
}

@media (max-width: 390px) {
  body[data-active-step="2"] .step2-meaning-switch {
    grid-template-columns: 1fr;
  }

  body[data-active-step="2"] .step2-interpret-btn {
    min-height: 66px;
  }
}


body.step2-extended-set[data-active-step="2"] .interactive-board {
  height: 430px;
}

@media (max-width: 700px) {
  body.step2-extended-set[data-active-step="2"] .interactive-board {
    height: 365px !important;
    min-height: 340px !important;
  }
}

body.step2-story-mode[data-active-step="2"] .token-theme-bar { display:none !important; }


/* ============================================================
   STEP 2 — SAME-BOARD SHARING POLISH
   ============================================================ */
.hidden {
  display: none !important;
}

/* Multiples/Common Multiples belong to Steps 9–10 only. */
body:not([data-active-step="9"]):not([data-active-step="10"]) #lcmTracksContainer {
  display: none !important;
}

/* Mode B target groups now sit inside the same interactive board. */
body[data-active-step="2"] .interactive-board.step2-share-board {
  min-height: 520px;
}

body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer {
  position: absolute;
  z-index: 60;
  top: 12px;
  left: 12px;
  right: 12px;
  margin: 0 !important;
  padding: 0 !important;
  border: 0 !important;
  display: grid;
  grid-template-columns: repeat(var(--share-cols, 3), minmax(0, 1fr));
  gap: 7px;
  pointer-events: none;
}

body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer .bucket {
  pointer-events: auto;
  min-height: 72px;
  padding: 7px 8px;
  border: 2px dashed color-mix(in srgb, var(--lab-indigo) 48%, var(--lab-border));
  border-radius: 17px;
  background:
    radial-gradient(circle at 50% 115%, rgba(99,102,241,.11), transparent 60%),
    color-mix(in srgb, var(--board-bg) 93%, var(--lab-indigo) 7%);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.035);
  transition:
    transform .16s cubic-bezier(.2,.9,.3,1),
    border-color .16s ease,
    background .16s ease,
    box-shadow .16s ease;
}

body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer .bucket.hovered {
  transform: translateY(-2px) scale(1.035);
  border-style: solid;
  border-color: var(--lab-indigo);
  background: color-mix(in srgb, var(--lab-indigo) 13%, var(--board-bg));
  box-shadow:
    0 0 0 2px color-mix(in srgb, var(--lab-indigo) 18%, transparent),
    0 10px 24px rgba(79,70,229,.15);
}

body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer .bucket.correct {
  border-style: solid;
  border-color: var(--lab-green);
}

body[data-active-step="2"] .interactive-board.step2-share-board .bucket-title {
  width: 100%;
  margin: 0 0 4px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  font-size: .65rem;
}

body[data-active-step="2"] .interactive-board.step2-share-board .bucket-count {
  min-width: 23px;
  padding: 2px 6px;
  border-radius: 999px;
  text-align: center;
  background: color-mix(in srgb, var(--lab-indigo) 11%, transparent);
  color: var(--lab-text-main);
  font-weight: 900;
}

body[data-active-step="2"] .interactive-board.step2-share-board .bucket-items {
  min-height: 34px;
  gap: 2px;
}

/* Pickup: visually lift the object from the surface. */
body[data-active-step="2"] .token.dragging {
  transform: translateY(-6px) scale(1.13) !important;
  z-index: 220;
  filter: drop-shadow(0 12px 12px rgba(0,0,0,.24));
  cursor: grabbing;
  transition:
    transform .12s cubic-bezier(.2,.9,.3,1),
    filter .12s ease !important;
}

body[data-active-step="2"] .token.snapping-to-bucket,
body[data-active-step="2"] .token.returning {
  z-index: 230;
  pointer-events: none;
}

/* Since targets are moved into the board, no external bucket strip remains. */
body[data-active-step="2"] .interactive-board-wrapper > #sharingBucketsContainer {
  display: none !important;
}

@media (max-width: 700px) {
  body[data-active-step="2"] .interactive-board.step2-share-board {
    height: 520px !important;
    min-height: 520px !important;
  }

  body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer {
    top: 9px;
    left: 8px;
    right: 8px;
    gap: 5px;
  }

  body[data-active-step="2"] .interactive-board.step2-share-board #sharingBucketsContainer .bucket {
    min-height: 64px;
    padding: 5px 6px;
    border-radius: 13px;
  }

  body[data-active-step="2"] .interactive-board.step2-share-board .bucket-title {
    font-size: .57rem;
  }

  body[data-active-step="2"] .interactive-board.step2-share-board .bucket-token-mini {
    width: 18px;
    height: 18px;
    flex-basis: 18px;
    font-size: 14px;
  }
}

@media (max-width: 390px) {
  body[data-active-step="2"] .interactive-board.step2-share-board {
    height: 555px !important;
    min-height: 555px !important;
  }
}


/* ============================================================
   STEP 2 — CONCEPT BRIDGE + 5-QUESTION MINI CHALLENGE
   ============================================================ */
.step2-bridge-card {
  margin-top: 9px;
  padding: 10px;
  border: 1px solid color-mix(in srgb, var(--lab-indigo) 28%, var(--lab-border));
  border-radius: 14px;
  background: color-mix(in srgb, var(--lab-indigo) 5%, var(--lab-bg-card));
}

.step2-bridge-title {
  margin-bottom: 8px;
  color: var(--lab-text-main);
  font-size: .73rem;
  font-weight: 900;
}

.step2-bridge-flow {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: stretch;
  gap: 6px;
}

.step2-bridge-node {
  min-width: 0;
  padding: 8px;
  border: 1px solid var(--lab-border);
  border-radius: 11px;
  background: var(--lab-bg-card);
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
}

.step2-bridge-node span {
  color: var(--lab-text-muted);
  font-size: .57rem;
  font-weight: 800;
}

.step2-bridge-node strong {
  color: var(--lab-text-main);
  font-size: .67rem;
  line-height: 1.35;
}

.step2-bridge-node.equation strong {
  color: var(--lab-indigo);
  font-size: .78rem;
  white-space: nowrap;
}

.step2-bridge-arrow {
  display: none;
}

body[data-active-step="2"] .lab-challenge-section {
  display: block;
}

body[data-active-step="2"] .challenge-card {
  border-left-color: var(--lab-indigo);
  border-color: color-mix(in srgb, var(--lab-indigo) 28%, var(--lab-border));
}

body[data-active-step="2"] .challenge-badge {
  color: var(--lab-indigo);
}

body[data-active-step="2"] .challenge-question {
  line-height: 1.55;
}

.step2-challenge-number {
  display: inline-block;
  margin-right: 7px;
  padding: 3px 8px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--lab-indigo) 11%, transparent);
  color: var(--lab-indigo);
  font-weight: 900;
}

body[data-active-step="2"] .challenge-question small {
  color: var(--lab-text-muted);
  font-size: .78rem;
  font-weight: 800;
}

.step2-challenge-choice {
  min-width: 155px;
  min-height: 44px;
  font-weight: 900;
}

.step2-challenge-choice.correct {
  border-color: var(--lab-green) !important;
  color: var(--lab-green) !important;
  background: color-mix(in srgb, var(--lab-green) 9%, transparent) !important;
}

.step2-challenge-choice.wrong {
  border-color: var(--lab-red) !important;
  color: var(--lab-red) !important;
  background: color-mix(in srgb, var(--lab-red) 8%, transparent) !important;
}

body[data-active-step="2"] .challenge-feedback.step2-quiz-feedback {
  display: flex;
  width: fit-content;
  max-width: 100%;
  padding: 7px 10px;
  border-radius: 10px;
  background: color-mix(in srgb, var(--lab-green) 7%, transparent);
}

body[data-active-step="2"] .challenge-feedback.step2-quiz-feedback.wrong {
  color: var(--lab-red);
  background: color-mix(in srgb, var(--lab-red) 7%, transparent);
}

.step2-challenge-result {
  flex: 1 1 300px;
  display: grid;
  gap: 4px;
  padding: 10px 12px;
  border: 1px solid var(--lab-border);
  border-radius: 12px;
}

.step2-challenge-result.passed {
  border-color: color-mix(in srgb, var(--lab-green) 48%, var(--lab-border));
  background: color-mix(in srgb, var(--lab-green) 7%, transparent);
}

.step2-challenge-result.retry {
  border-color: color-mix(in srgb, var(--lab-orange) 48%, var(--lab-border));
  background: color-mix(in srgb, var(--lab-orange) 7%, transparent);
}

.step2-challenge-result strong { color: var(--lab-text-main); }
.step2-challenge-result span { color: var(--lab-text-muted); font-size: .73rem; font-weight: 700; }
.step2-challenge-retry { min-height: 44px; }

@media (max-width: 700px) {
  .step2-bridge-card { padding: 8px; }
  .step2-bridge-flow { grid-template-columns: 1fr 1fr; gap: 6px; }
  .step2-bridge-node { padding: 7px; }
  .step2-bridge-node span { font-size: .54rem; }
  .step2-bridge-node strong { font-size: .62rem; }
  .step2-bridge-node.equation strong { font-size: .7rem; }
  body[data-active-step="2"] .challenge-card { padding: 14px; }
  body[data-active-step="2"] .challenge-header { gap: 8px; align-items: flex-start; }
  .step2-challenge-choice { min-width: 0; flex: 1 1 calc(50% - 4px); font-size: .7rem; }
}

@media (max-width: 390px) {
  .step2-bridge-flow { grid-template-columns: 1fr; }
  .step2-challenge-choice { flex-basis: 100%; }
}

/* Steps 1–2 are open exploration: learners choose when/where to continue. */
body[data-active-step="1"] .nav-btn-next,
body[data-active-step="2"] .nav-btn-next {
  display: none !important;
}

/* ============================================================
   STEP 3 — REMAINDERS
   ============================================================ */
body[data-active-step="3"] .step3-equation-card .step1-equation-question {
  display: inline-flex;
  align-items: baseline;
  gap: 5px;
}
body[data-active-step="3"] .step3-equation-card .step1-equation-question small {
  font-size: .62em;
  color: var(--lab-orange);
  font-weight: 900;
}

.step3-concept-card,
.step3-practice-card,
.step3-bridge-card {
  margin-top: 10px;
  border: 1px solid var(--lab-border);
  border-radius: 15px;
  background: color-mix(in srgb, var(--lab-bg-card) 94%, var(--lab-orange) 6%);
  padding: 11px;
}

.step3-concept-title,
.step3-bridge-title,
.step3-answer-title {
  color: var(--lab-text-main);
  font-size: .76rem;
  line-height: 1.35;
  font-weight: 900;
}

.step3-concept-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 7px;
  margin-top: 9px;
}
.step3-concept-grid > div {
  position: relative;
  min-width: 0;
  padding: 9px 8px 8px 33px;
  border: 1px solid var(--lab-border);
  border-radius: 11px;
  background: var(--lab-bg-card);
}
.step3-concept-grid > div > span {
  position: absolute;
  left: 8px;
  top: 9px;
  width: 18px;
  height: 18px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: color-mix(in srgb, var(--lab-orange) 18%, transparent);
  color: var(--lab-orange);
  font-size: .59rem;
  font-weight: 900;
}
.step3-concept-grid strong,
.step3-concept-grid small { display: block; }
.step3-concept-grid strong { font-size: .68rem; color: var(--lab-text-main); }
.step3-concept-grid small { margin-top: 3px; font-size: .58rem; color: var(--lab-text-muted); line-height: 1.35; }

.step3-explore-hint,
.step3-answer-feedback {
  margin-top: 8px;
  padding: 8px 9px;
  border-radius: 10px;
  background: color-mix(in srgb, var(--lab-indigo) 7%, transparent);
  color: var(--lab-text-muted);
  font-size: .64rem;
  font-weight: 700;
  line-height: 1.4;
}
.step3-discovery {
  margin-top: 9px;
  padding: 10px;
  border: 1px solid color-mix(in srgb, var(--lab-orange) 42%, var(--lab-border));
  border-radius: 11px;
  background: color-mix(in srgb, var(--lab-orange) 9%, var(--lab-bg-card));
  text-align: center;
}
.step3-discovery strong { display:block; color:var(--lab-orange); font-size:.92rem; }
.step3-discovery span { display:block; margin-top:3px; color:var(--lab-text-muted); font-size:.62rem; font-weight:700; }

.step3-prompt {
  margin: 8px 0 9px;
  color: var(--lab-text-main);
  font-size: .72rem;
  font-weight: 750;
  line-height: 1.45;
}
.step3-answer-grid {
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  gap: 6px;
  margin-top: 7px;
}
.step3-answer-btn,
.step3-challenge-choice {
  min-height: 42px;
  border: 1px solid var(--lab-border);
  border-radius: 10px;
  background: var(--lab-bg-card);
  color: var(--lab-text-main);
  font: inherit;
  font-size: .7rem;
  font-weight: 900;
  cursor: pointer;
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
}
.step3-answer-btn:not(:disabled):hover,
.step3-challenge-choice:not(:disabled):hover { transform: translateY(-1px); border-color:var(--lab-indigo); }
.step3-answer-grid.locked { opacity:.5; }
.step3-answer-btn:disabled { cursor:not-allowed; }
.step3-answer-btn.correct,
.step3-challenge-choice.correct { border-color:var(--lab-green)!important; background:color-mix(in srgb,var(--lab-green) 13%,var(--lab-bg-card)); color:var(--lab-green); }
.step3-answer-btn.wrong,
.step3-challenge-choice.wrong { border-color:var(--lab-red)!important; background:color-mix(in srgb,var(--lab-red) 10%,var(--lab-bg-card)); color:var(--lab-red); }
.step3-answer-feedback.correct { color:var(--lab-green); background:color-mix(in srgb,var(--lab-green) 9%,transparent); }
.step3-answer-feedback.wrong { color:var(--lab-red); background:color-mix(in srgb,var(--lab-red) 8%,transparent); }

.step3-bridge-card { border-color: color-mix(in srgb, var(--lab-orange) 30%, var(--lab-border)); }
.step3-bridge-row {
  display:flex;
  justify-content:space-between;
  gap:8px;
  margin-top:7px;
  padding:7px 8px;
  border-radius:9px;
  background:var(--lab-bg-card);
  color:var(--lab-text-muted);
  font-size:.62rem;
}
.step3-bridge-row strong { color:var(--lab-text-main); text-align:right; }
.step3-bridge-row.remainder strong { color:var(--lab-orange); }
.step3-identity {
  margin-top:8px;
  padding:8px;
  border-radius:9px;
  text-align:center;
  background:color-mix(in srgb,var(--lab-indigo) 8%,transparent);
  color:var(--lab-indigo);
  font-size:.8rem;
  font-weight:900;
}
.step3-rule {
  margin-top:6px;
  color:var(--lab-orange);
  font-size:.64rem;
  font-weight:900;
  text-align:center;
}

.step3-board-result {
  display:flex;
  align-items:center;
  justify-content:center;
  flex-wrap:wrap;
  gap:5px 10px;
  width:100%;
}
.step3-board-result strong { color:var(--lab-indigo); }
.step3-board-result b { color:var(--lab-orange); }
.step3-board-result em { color:var(--lab-orange); font-style:normal; font-weight:900; }
body[data-active-step="3"] .token.remainder {
  box-shadow: 0 0 0 3px color-mix(in srgb,var(--lab-orange) 28%,transparent), 0 8px 18px rgba(0,0,0,.12);
}
body[data-active-step="3"] .remainder-label {
  color:var(--lab-orange);
  font-weight:900;
}
.step3-rem-monitor { color:var(--lab-orange)!important; }
.step3-monitor-rule { margin-top:7px; border-top:1px dashed var(--lab-border); padding-top:7px; }
.step3-monitor-rule .monitor-val { color:var(--lab-orange); font-weight:900; }
.step3-monitor-equation .monitor-val { color:var(--lab-indigo); }

body.step3-extended-set[data-active-step="3"] .interactive-board {
  min-height: 500px;
  height: 500px;
}

@media (max-width:700px) {
  body[data-active-step="3"] .step3-concept-card,
  body[data-active-step="3"] .step3-practice-card,
  body[data-active-step="3"] .step3-bridge-card { padding:9px; }
  .step3-concept-grid { grid-template-columns:1fr; }
  .step3-answer-grid { grid-template-columns:1fr 1fr; }
  .step3-answer-btn { min-height:40px; font-size:.67rem; }
  body.step3-extended-set[data-active-step="3"] .interactive-board { min-height:560px; height:560px; }
}

@media (max-width:390px) {
  .step3-answer-grid { grid-template-columns:1fr; }
}

/* Step 3 follows the same open-exploration navigation model as Steps 1–2. */
body[data-active-step="3"] .nav-btn-next { display:none!important; }
body[data-active-step="3"] .token.remainder-focus {
  animation: step3RemainderFocus .62s ease both;
}
@keyframes step3RemainderFocus {
  0%,100% { transform: scale(1); }
  45% { transform: scale(1.16); filter: brightness(1.18); }
}
.step3-board-result.practice-ready strong { color:var(--lab-green); }
.step3-zero-note {
  margin-top:6px;
  text-align:center;
  color:var(--lab-text-muted);
  font-size:.59rem;
  font-weight:700;
}

/* Step 3 remainder cluster: one badge for the whole leftover set, never text over each object. */
.step3-remainder-cluster-label {
  position: absolute;
  z-index: 118;
  transform: translate(-50%, -100%) translateY(-8px);
  pointer-events: none;
  white-space: nowrap;
  padding: 5px 10px;
  border-radius: 999px;
  border: 1px solid color-mix(in srgb, var(--lab-orange) 58%, transparent);
  background: color-mix(in srgb, var(--lab-bg-card) 86%, var(--lab-orange) 14%);
  color: var(--lab-orange);
  box-shadow: 0 6px 18px rgba(245, 158, 11, .16);
  font-size: .66rem;
  font-weight: 900;
}

.step3-random-note {
  margin-top: 7px;
  text-align: center;
  color: var(--lab-text-muted);
  font-size: .58rem;
  line-height: 1.35;
  font-weight: 700;
}

body[data-active-step="3"] .token.remainder {
  z-index: 20;
}

@media (max-width: 700px) {
  .step3-remainder-cluster-label { font-size: .62rem; padding: 4px 8px; }
  .step3-random-note { font-size: .56rem; }
}

/* ============================================================
   STEP 4 — EXACT DIVISION / DIVISIBILITY
   ============================================================ */
body[data-active-step="4"] .nav-btn-next { display:none!important; }

.step4-number-card {
  margin-top: 10px;
  padding: 12px;
  border: 1px solid color-mix(in srgb,var(--lab-indigo) 28%,var(--lab-border));
  border-radius: 14px;
  background: color-mix(in srgb,var(--lab-indigo) 7%,var(--lab-bg-card));
  text-align: center;
}
.step4-number-card small,
.step4-number-card span { display:block; color:var(--lab-text-muted); font-size:.6rem; font-weight:700; }
.step4-number-card strong { display:block; margin:2px 0; color:var(--lab-indigo); font-size:1.6rem; line-height:1; font-weight:950; }
.step4-divisor-title { margin:10px 0 6px; color:var(--lab-text-main); font-size:.67rem; font-weight:900; }
.step4-divisors-grid { grid-template-columns:repeat(4,minmax(0,1fr)); }
.step4-divisors-grid .div-btn.current-divisor { outline:2px solid color-mix(in srgb,var(--lab-indigo) 68%,transparent); outline-offset:2px; }

.step4-equation-card .step1-equation-question { font-size:.72rem; color:var(--lab-orange); font-weight:900; }
.step4-concept-card,
.step4-practice-card,
.step4-bridge-card {
  margin-top:10px;
  padding:11px;
  border:1px solid var(--lab-border);
  border-radius:15px;
  background:color-mix(in srgb,var(--lab-bg-card) 95%,var(--lab-green) 5%);
}
.step4-concept-title,
.step4-bridge-title,
.step4-predict-title { color:var(--lab-text-main); font-size:.75rem; line-height:1.35; font-weight:900; }
.step4-rule-grid { display:grid; grid-template-columns:1fr 1fr; gap:7px; margin-top:9px; }
.step4-rule-grid>div { padding:9px; border:1px solid var(--lab-border); border-radius:11px; background:var(--lab-bg-card); }
.step4-rule-grid span,.step4-rule-grid strong,.step4-rule-grid small { display:block; }
.step4-rule-grid span { font-size:.61rem; color:var(--lab-text-muted); font-weight:800; }
.step4-rule-grid strong { margin-top:2px; font-size:.72rem; color:var(--lab-text-main); }
.step4-rule-grid>div:first-child strong { color:var(--lab-green); }
.step4-rule-grid>div:last-child strong { color:var(--lab-orange); }
.step4-rule-grid small { margin-top:3px; color:var(--lab-text-muted); font-size:.57rem; line-height:1.35; }
.step4-explore-hint,.step4-answer-feedback {
  margin-top:8px; padding:8px 9px; border-radius:10px;
  background:color-mix(in srgb,var(--lab-indigo) 7%,transparent);
  color:var(--lab-text-muted); font-size:.63rem; font-weight:700; line-height:1.4;
}
.step4-discovery { margin-top:9px; padding:10px; border:1px solid var(--lab-border); border-radius:11px; text-align:center; }
.step4-discovery strong,.step4-discovery span { display:block; }
.step4-discovery strong { font-size:.88rem; font-weight:950; }
.step4-discovery span { margin-top:3px; font-size:.61rem; color:var(--lab-text-muted); font-weight:750; }
.step4-discovery.exact { border-color:color-mix(in srgb,var(--lab-green) 45%,var(--lab-border)); background:color-mix(in srgb,var(--lab-green) 8%,var(--lab-bg-card)); }
.step4-discovery.exact strong { color:var(--lab-green); }
.step4-discovery.not-exact { border-color:color-mix(in srgb,var(--lab-orange) 45%,var(--lab-border)); background:color-mix(in srgb,var(--lab-orange) 8%,var(--lab-bg-card)); }
.step4-discovery.not-exact strong { color:var(--lab-orange); }
.step4-tested-summary { display:flex; align-items:center; justify-content:space-between; gap:8px; margin-top:7px; padding:7px 8px; border-radius:9px; background:var(--lab-bg-card); color:var(--lab-text-muted); font-size:.59rem; }
.step4-tested-summary strong { color:var(--lab-green); text-align:right; }

.step4-prompt { margin:8px 0 9px; color:var(--lab-text-main); font-size:.72rem; font-weight:750; line-height:1.45; }
.step4-predict-title { margin-bottom:7px; font-size:.64rem; color:var(--lab-text-muted); }
.step4-predict-grid { display:grid; grid-template-columns:1fr 1fr; gap:7px; }
.step4-predict-btn,.step4-challenge-choice {
  min-height:42px; padding:8px; border:1px solid var(--lab-border); border-radius:10px;
  background:var(--lab-bg-card); color:var(--lab-text-main); font:inherit; font-size:.68rem; font-weight:900;
  cursor:pointer; transition:transform .15s ease,border-color .15s ease,background .15s ease;
}
.step4-predict-btn:not(:disabled):hover,.step4-challenge-choice:not(:disabled):hover { transform:translateY(-1px); border-color:var(--lab-indigo); }
.step4-predict-btn.correct,.step4-challenge-choice.correct { border-color:var(--lab-green)!important; background:color-mix(in srgb,var(--lab-green) 13%,var(--lab-bg-card)); color:var(--lab-green); }
.step4-predict-btn.wrong,.step4-challenge-choice.wrong { border-color:var(--lab-red)!important; background:color-mix(in srgb,var(--lab-red) 10%,var(--lab-bg-card)); color:var(--lab-red); }
.step4-answer-feedback.correct { color:var(--lab-green); background:color-mix(in srgb,var(--lab-green) 9%,transparent); }
.step4-answer-feedback.wrong { color:var(--lab-red); background:color-mix(in srgb,var(--lab-red) 8%,transparent); }

.step4-bridge-card.exact { border-color:color-mix(in srgb,var(--lab-green) 34%,var(--lab-border)); }
.step4-bridge-card.not-exact { border-color:color-mix(in srgb,var(--lab-orange) 34%,var(--lab-border)); }
.step4-identity { margin-top:8px; padding:8px; border-radius:9px; text-align:center; background:color-mix(in srgb,var(--lab-indigo) 8%,transparent); color:var(--lab-indigo); font-size:.82rem; font-weight:950; }
.step4-bridge-result { display:flex; justify-content:space-between; gap:8px; margin-top:7px; padding:7px 8px; border-radius:9px; background:var(--lab-bg-card); color:var(--lab-text-muted); font-size:.62rem; }
.step4-bridge-card.exact .step4-bridge-result b { color:var(--lab-green); }
.step4-bridge-card.not-exact .step4-bridge-result b { color:var(--lab-orange); }
.step4-next-link { margin-top:7px; color:var(--lab-text-muted); font-size:.58rem; line-height:1.4; font-weight:700; }

/* Board before prediction: objects are visible, but no grouping/remainder clue is revealed. */
.step4-neutral-grid {
  position:absolute; inset:30px; z-index:5;
  display:grid; grid-template-columns:repeat(var(--step4-neutral-count),minmax(20px,1fr));
  place-content:center; align-items:center; justify-items:center; gap:8px;
  pointer-events:none;
}
.step4-neutral-grid .token.step4-mini-token,
.step4-cluster-grid .token.step4-mini-token {
  position:static!important; left:auto!important; top:auto!important;
  width:30px; height:30px; min-width:30px; min-height:30px;
  transform:none!important; margin:0!important; font-size:18px;
}
.step4-neutral-token { opacity:.92; animation:step4NeutralIn .28s ease both; }
@keyframes step4NeutralIn { from{opacity:0;transform:scale(.75)!important} to{opacity:.92;transform:scale(1)!important} }

/* After checking, each full group becomes one compact visual cluster. */
.step4-cluster-grid {
  position:absolute; inset:22px; z-index:6; overflow:auto;
  display:grid; grid-template-columns:repeat(auto-fit,minmax(105px,1fr));
  align-content:center; gap:9px; padding:4px;
  pointer-events:none;
}
.step4-group-cluster {
  min-height:70px; padding:20px 7px 7px; position:relative;
  display:flex; align-items:center; justify-content:center;
  border:1px solid color-mix(in srgb,var(--lab-indigo) 30%,var(--lab-border));
  border-radius:16px; background:color-mix(in srgb,var(--lab-indigo) 5%,var(--lab-bg-card));
  animation:step4ClusterPop .3s ease both;
}
@keyframes step4ClusterPop { from{opacity:0;transform:translateY(7px) scale(.96)} to{opacity:1;transform:none} }
.step4-cluster-label {
  position:absolute; top:5px; left:8px; right:8px; text-align:center;
  color:var(--lab-text-muted); font-size:.54rem; font-weight:900; white-space:nowrap;
}
.step4-cluster-items { display:flex; align-items:center; justify-content:center; flex-wrap:wrap; gap:4px; max-width:150px; }
.step4-remainder-cluster { border-color:color-mix(in srgb,var(--lab-orange) 62%,var(--lab-border)); background:color-mix(in srgb,var(--lab-orange) 10%,var(--lab-bg-card)); }
.step4-remainder-cluster .step4-cluster-label { color:var(--lab-orange); }
.step4-remainder-cluster .token { box-shadow:0 0 0 2px color-mix(in srgb,var(--lab-orange) 28%,transparent),0 5px 12px rgba(0,0,0,.12); }

.step4-board-result { width:100%; display:flex; align-items:center; justify-content:center; flex-wrap:wrap; gap:5px 10px; }
.step4-board-result.exact strong,.step4-board-result.exact b { color:var(--lab-green); }
.step4-board-result.not-exact strong,.step4-board-result.not-exact b { color:var(--lab-orange); }
.step4-monitor-exact { color:var(--lab-green)!important; font-weight:950; }
.step4-monitor-not-exact { color:var(--lab-orange)!important; font-weight:950; }
.step4-monitor-result { margin-top:7px; border-top:1px dashed var(--lab-border); padding-top:7px; }
.step4-monitor-equation .monitor-val { color:var(--lab-indigo); }

@media (max-width:700px) {
  .step4-rule-grid { grid-template-columns:1fr; }
  .step4-concept-card,.step4-practice-card,.step4-bridge-card { padding:9px; }
  .step4-cluster-grid { inset:14px 10px; grid-template-columns:repeat(auto-fit,minmax(82px,1fr)); gap:6px; }
  .step4-group-cluster { min-height:62px; padding:18px 5px 5px; border-radius:12px; }
  .step4-neutral-grid { inset:18px 10px; gap:5px; }
  .step4-neutral-grid .token.step4-mini-token,.step4-cluster-grid .token.step4-mini-token { width:25px; height:25px; min-width:25px; min-height:25px; font-size:15px; }
  body.step4-extended-set[data-active-step="4"] .interactive-board { min-height:500px; height:500px; }
}
@media (max-width:390px) {
  .step4-predict-grid { grid-template-columns:1fr; }
  .step4-divisors-grid { grid-template-columns:repeat(3,minmax(0,1fr)); }
  .step4-cluster-grid { grid-template-columns:repeat(auto-fit,minmax(72px,1fr)); }
}