<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 10px;
      width: 100%;
      min-height: 100%;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .grid-container {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      width: 100%;
      max-width: 620px;
      margin: 0 auto;
    }

    @media (max-width: 480px) {
      .grid-container {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }

    .panel-card {
      border-radius: 14px;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      position: relative;
      min-height: 220px;
      cursor: pointer;
      user-select: none;
      transition: transform 0.2s ease, box-shadow 0.2s ease;
    }

    .panel-card.valid {
      background: #f0fdf9;
      border: 1.5px solid #a7f3d0;
    }
    .panel-card.invalid {
      background: #fff5f5;
      border: 1.5px solid #fecaca;
    }

    .badge {
      display: inline-flex;
      align-items: center;
      gap: 5px;
      font-size: 13px;
      font-weight: 700;
      padding: 4px 10px;
      border-radius: 20px;
      letter-spacing: 0.2px;
    }

    .badge.valid {
      background: #2ec4b6;
      color: #ffffff;
    }
    .badge.invalid {
      background: #e71d36;
      color: #ffffff;
    }

    .stage {
      display: flex;
      align-items: flex-end;
      justify-content: center;
      gap: 20px;
      height: 130px;
      width: 100%;
      padding-bottom: 4px;
      position: relative;
    }

    .item-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
    }

    .item-label {
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      white-space: nowrap;
    }

    /* Valid Tree Visuals */
    .tree-stack {
      display: flex;
      flex-direction: column-reverse;
      gap: 2px;
      width: 44px;
    }

    .segment {
      width: 100%;
      height: 32px;
      border-radius: 6px;
      background: #d1fae5;
      border: 1.5px solid #10b981;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 10px;
      font-weight: 700;
      color: #065f46;
      transition: background 0.3s ease;
    }

    .panel-card.valid:hover .segment {
      background: #a7f3d0;
    }

    .tree-icon {
      font-size: 18px;
      line-height: 1;
      margin-bottom: -4px;
    }

    /* Invalid Items Visuals */
    .invalid-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-end;
    }

    .bar-tree {
      width: 44px;
      height: 98px;
      border-radius: 6px;
      background: #e2e8f0;
      border: 1.5px solid #94a3b8;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      font-size: 11px;
      font-weight: 700;
      color: #475569;
    }

    .bag-scale {
      width: 52px;
      height: 60px;
      border-radius: 10px;
      background: #fee2e2;
      border: 1.5px solid #f87171;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      font-size: 11px;
      font-weight: 700;
      color: #991b1b;
      gap: 2px;
    }

    .unit-tag {
      font-size: 9px;
      padding: 1px 4px;
      border-radius: 4px;
      background: rgba(0,0,0,0.06);
      font-weight: 600;
    }

    .vs-symbol {
      align-self: center;
      font-size: 16px;
      font-weight: 800;
      color: #94a3b8;
      margin-bottom: 12px;
    }

    .cross-overlay {
      position: absolute;
      top: 45%;
      left: 50%;
      transform: translate(-50%, -50%);
      font-size: 32px;
      color: #e71d36;
      font-weight: 900;
      filter: drop-shadow(0 2px 4px rgba(231,29,54,0.25));
    }

    .result-pill {
      font-size: 12px;
      font-weight: 700;
      padding: 6px 12px;
      border-radius: 8px;
      text-align: center;
      width: 100%;
      box-sizing: border-box;
    }

    .result-pill.valid {
      background: #e6fffa;
      color: #0f766e;
      border: 1px solid #99f6e4;
    }

    .result-pill.invalid {
      background: #fff1f2;
      color: #be123c;
      border: 1px solid #fecdd3;
    }
  </style>
</head>
<body>
  <div class="grid-container">
    
    <div class="panel-card valid" title="Valid Ratio: Same attribute (Length)">
      <div class="badge valid">✓ Valid Ratio</div>

      <div class="stage">
        
        <div class="item-col">
          <span class="tree-icon">🌲</span>
          <div class="tree-stack">
            <div class="segment">4 ft</div>
            <div class="segment">4 ft</div>
            <div class="segment">4 ft</div>
          </div>
          <span class="item-label">Tree A (12 ft)</span>
        </div>

        <div class="vs-symbol">:</div>

        
        <div class="item-col">
          <span class="tree-icon">🌲</span>
          <div class="tree-stack" style="width: 44px;">
            <div class="segment">4 ft</div>
          </div>
          <span class="item-label">Tree B (4 ft)</span>
        </div>
      </div>

      <div class="result-pill valid">
        12 ft : 4 ft = 3× as tall
      </div>
    </div>

    
    <div class="panel-card invalid" title="Invalid Ratio: Different attributes">
      <div class="badge invalid">✗ Invalid Comparison</div>

      <div class="stage">
        
        <div class="item-col">
          <span class="tree-icon">🌲</span>
          <div class="bar-tree">
            <span>12 ft</span>
            <span class="unit-tag">Height</span>
          </div>
          <span class="item-label">Tree A</span>
        </div>

        <div class="vs-symbol">vs</div>

        
        <div class="item-col">
          <div class="bag-scale">
            <span style="font-size: 16px;">🍎</span>
            <span>6 lbs</span>
            <span class="unit-tag">Weight</span>
          </div>
          <span class="item-label">Apples</span>
        </div>

        <div class="cross-overlay">⊘</div>
      </div>

      <div class="result-pill invalid">
        Cannot compare height to weight
      </div>
    </div>
  </div>
</body>
</html>

Understanding Ratios as Multiplicative Comparisons

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <script src="{{VENDOR_CDN}}/classace-diagram.js"></script>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    }
    :root {
      --indigo: #4361ee;
      --indigo-light: #eef2ff;
      --amber: #f72585;
      --amber-light: #fdf2f8;
      --text: #1e2945;
      --muted: #64748b;
      --border: #e2e8f0;
      --bg-subtle: #f8fafc;
    }
    body {
      background: #ffffff;
      color: var(--text);
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    /* Stepper navigation bar */
    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 520px;
      gap: 8px;
      margin-bottom: 8px;
    }
    .tabs {
      display: flex;
      gap: 6px;
      flex: 1;
    }
    .tab-btn {
      flex: 1;
      padding: 6px 4px;
      font-size: 13px;
      font-weight: 700;
      border: 1px solid var(--border);
      border-radius: 8px;
      background: var(--bg-subtle);
      color: var(--muted);
      cursor: pointer;
      text-align: center;
      transition: all 0.2s ease;
    }
    .tab-btn.active {
      background: var(--indigo);
      color: #ffffff;
      border-color: var(--indigo);
      box-shadow: 0 2px 6px rgba(67, 97, 238, 0.3);
    }
    .ctrl-btn {
      padding: 6px 10px;
      font-size: 13px;
      font-weight: 600;
      border: 1px solid var(--border);
      border-radius: 8px;
      background: #ffffff;
      color: var(--text);
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* Main display stage */
    .stage {
      width: 100%;
      max-width: 520px;
      background: #ffffff;
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      position: relative;
    }

    /* Step Banner / Math Formula */
    .formula-badge {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 8px;
      background: var(--bg-subtle);
      border-radius: 8px;
      font-size: 15px;
      font-weight: 700;
      color: var(--text);
      min-height: 40px;
      text-align: center;
    }
    .badge-maya {
      color: var(--indigo);
    }
    .badge-leo {
      color: var(--amber);
    }

    /* Visual Model Comparison */
    .model-area {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .runner-row {
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .runner-label {
      width: 52px;
      font-size: 13px;
      font-weight: 700;
      display: flex;
      flex-direction: column;
      line-height: 1.1;
    }
    .runner-label small {
      font-size: 11px;
      font-weight: 600;
      color: var(--muted);
    }
    .laps-container {
      display: flex;
      flex: 1;
      gap: 6px;
      align-items: center;
    }

    /* Group Box styling for multiplicative reasoning */
    .lap-group {
      display: flex;
      gap: 3px;
      padding: 4px;
      border-radius: 8px;
      border: 1.5px dashed transparent;
      transition: all 0.3s ease;
      background: transparent;
    }
    .lap-group.highlight-maya {
      border-color: var(--indigo);
      background: var(--indigo-light);
    }
    .lap-group.highlight-leo {
      border-color: var(--amber);
      background: var(--amber-light);
    }

    .lap-dot {
      width: 18px;
      height: 22px;
      border-radius: 4px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 11px;
      font-weight: 700;
      color: #ffffff;
      transition: transform 0.2s ease, opacity 0.2s ease;
    }
    .lap-dot.maya {
      background: var(--indigo);
    }
    .lap-dot.leo {
      background: var(--amber);
    }

    .multiplier-tag {
      font-size: 11px;
      font-weight: 700;
      color: var(--indigo);
      background: #ffffff;
      border: 1px solid var(--indigo);
      border-radius: 4px;
      padding: 1px 4px;
      white-space: nowrap;
      display: none;
    }
    .show-multipliers .multiplier-tag {
      display: block;
    }

    /* Bottom Conclusion Banner */
    .conclusion-banner {
      width: 100%;
      max-width: 520px;
      background: var(--indigo-light);
      border: 1px solid var(--indigo);
      border-radius: 8px;
      padding: 8px 12px;
      font-size: 13px;
      font-weight: 700;
      color: var(--indigo);
      text-align: center;
      transition: all 0.3s ease;
    }

    /* Responsive scaling */
    @media (max-width: 420px) {
      .runner-label { width: 44px; font-size: 12px; }
      .lap-dot { width: 14px; height: 18px; font-size: 9px; }
      .lap-group { gap: 2px; padding: 2px; }
      .formula-badge { font-size: 13px; }
      .conclusion-banner { font-size: 12px; }
    }
  </style>
</head>
<body>

  
  <div class="nav-bar">
    <div class="tabs">
      <button class="tab-btn active" id="tab0">1. Count</button>
      <button class="tab-btn" id="tab1">2. Ratio</button>
      <button class="tab-btn" id="tab2">3. Scale (÷)</button>
    </div>
    <button class="ctrl-btn" id="playBtn" title="Play / Pause">⏸</button>
  </div>

  
  <div class="stage" id="stage">
    <div class="formula-badge" id="formulaText">
      Attribute: <span class="badge-maya">12 Laps</span> vs <span class="badge-leo">4 Laps</span>
    </div>

    <div class="model-area" id="modelArea">
      
      <div class="runner-row">
        <div class="runner-label">
          <span style="color: var(--indigo);">Maya</span>
          <small id="mayaCountLabel">12 laps</small>
        </div>
        <div class="laps-container" id="mayaContainer">
          
          <div class="lap-group" id="mg1">
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
          </div>
          
          <div class="lap-group" id="mg2">
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
          </div>
          
          <div class="lap-group" id="mg3">
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
            <div class="lap-dot maya">🏃</div>
          </div>
        </div>
      </div>

      
      <div class="runner-row">
        <div class="runner-label">
          <span style="color: var(--amber);">Leo</span>
          <small id="leoCountLabel">4 laps</small>
        </div>
        <div class="laps-container">
          
          <div class="lap-group" id="lg1">
            <div class="lap-dot leo">🏃</div>
            <div class="lap-dot leo">🏃</div>
            <div class="lap-dot leo">🏃</div>
            <div class="lap-dot leo">🏃</div>
          </div>
        </div>
      </div>
    </div>
  </div>

  
  <div class="conclusion-banner" id="conclusion">
    Maya ran 3 times as many laps as Leo (ratio 3 : 1)
  </div>

  <script>
    const stepsData = [
      {
        formula: 'Attribute: <span class="badge-maya">Maya (12)</span> vs <span class="badge-leo">Leo (4)</span>',
        grouping: false,
        conclusion: 'Comparing quantities: 12 laps to 4 laps'
      },
      {
        formula: 'Ratio: Maya to Leo = <span class="badge-maya">12</span> : <span class="badge-leo">4</span>',
        grouping: false,
        conclusion: 'Written as ratio 12 : 4'
      },
      {
        formula: 'Scale factor: <span class="badge-maya">12</span> ÷ <span class="badge-leo">4</span> = <strong>3</strong> (3 equal groups of 4)',
        grouping: true,
        conclusion: 'Maya ran 3 times as many laps as Leo (ratio 3 : 1)'
      }
    ];

    let currentStep = 0;
    let timer = null;
    let isPlaying = true;

    function applyStep(index) {
      currentStep = index;
      const data = stepsData[index];

      // Update tabs
      for (let i = 0; i < 3; i++) {
        const tab = document.getElementById('tab' + i);
        if (i === index) {
          tab.classList.add('active');
        } else {
          tab.classList.remove('active');
        }
      }

      // Update Header & Banner
      document.getElementById('formulaText').innerHTML = data.formula;
      document.getElementById('conclusion').innerHTML = data.conclusion;

      // Update visual grouping highlights
      const mg1 = document.getElementById('mg1');
      const mg2 = document.getElementById('mg2');
      const mg3 = document.getElementById('mg3');
      const lg1 = document.getElementById('lg1');

      if (data.grouping) {
        mg1.classList.add('highlight-maya');
        mg2.classList.add('highlight-maya');
        mg3.classList.add('highlight-maya');
        lg1.classList.add('highlight-leo');
      } else {
        mg1.classList.remove('highlight-maya');
        mg2.classList.remove('highlight-maya');
        mg3.classList.remove('highlight-maya');
        lg1.classList.remove('highlight-leo');
      }
    }

    function startAutoPlay() {
      if (timer) clearInterval(timer);
      timer = setInterval(() => {
        const next = (currentStep + 1) % 3;
        applyStep(next);
      }, 3500);
    }

    function stopAutoPlay() {
      if (timer) clearInterval(timer);
      timer = null;
    }

    // Set up tab click interactions
    for (let i = 0; i < 3; i++) {
      const btn = document.getElementById('tab' + i);
      btn.addEventListener('click', () => {
        applyStep(i);
        if (isPlaying) {
          startAutoPlay(); // Reset timer cadence on user interaction
        }
      });
    }

    const playBtn = document.getElementById('playBtn');
    playBtn.addEventListener('click', () => {
      isPlaying = !isPlaying;
      if (isPlaying) {
        playBtn.textContent = '⏸';
        startAutoPlay();
      } else {
        playBtn.textContent = '▶';
        stopAutoPlay();
      }
    });

    // Initialize at resting state (Step 0) and start calm stepper
    applyStep(0);
    startAutoPlay();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      background-color: #f8f9fa;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      color: #1e2945;
      padding: 16px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .controls {
      display: flex;
      gap: 8px;
      margin-bottom: 20px;
      background: #e9ecef;
      padding: 4px;
      border-radius: 999px;
    }

    .btn {
      border: none;
      background: transparent;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #6b7280;
      border-radius: 999px;
      cursor: pointer;
      transition: all 0.25s ease;
    }

    .btn.active {
      background: #ffffff;
      color: #1e2945;
      box-shadow: 0 2px 6px rgba(0,0,0,0.08);
    }

    .diagram-area {
      width: 100%;
      max-width: 520px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .rope-row {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .rope-meta {
      display: flex;
      justify-content: space-between;
      align-items: baseline;
      font-size: 14px;
      font-weight: 700;
    }

    .rope-label {
      color: #1e2945;
    }

    .rope-len {
      font-variant-numeric: tabular-nums;
      color: #6b7280;
      font-size: 13px;
    }

    .bar-container {
      width: 100%;
      height: 48px;
      background: #e9ecef;
      border-radius: 10px;
      position: relative;
      overflow: hidden;
      display: flex;
    }

    .rope-your {
      width: 100%;
      height: 100%;
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      border-radius: 10px;
      overflow: hidden;
    }

    .segment {
      display: flex;
      align-items: center;
      justify-content: center;
      background: #00a896;
      color: #ffffff;
      font-weight: 700;
      font-size: 14px;
      border-right: 2px dashed rgba(255, 255, 255, 0.4);
      transition: background-color 0.3s ease, opacity 0.3s ease;
      position: relative;
    }

    .segment:last-child {
      border-right: none;
    }

    .segment-tag {
      position: absolute;
      top: -24px;
      font-size: 11px;
      font-weight: 700;
      color: #00a896;
      opacity: 0;
      transition: opacity 0.3s ease;
    }

    .rope-friend-wrap {
      width: 100%;
      display: flex;
    }

    .rope-friend {
      width: calc(100% / 3);
      height: 48px;
      background: #f26419;
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #ffffff;
      font-weight: 700;
      font-size: 14px;
      box-shadow: 0 2px 4px rgba(242, 100, 25, 0.2);
    }

    .bracket-layer {
      position: relative;
      height: 52px;
      width: 100%;
      margin-top: 4px;
    }

    .callout {
      position: absolute;
      inset: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 700;
      opacity: 0;
      transform: translateY(4px);
      transition: opacity 0.3s ease, transform 0.3s ease;
      pointer-events: none;
    }

    .callout.active {
      opacity: 1;
      transform: translateY(0);
    }

    .callout-additive {
      left: calc(100% / 3);
      width: calc(200% / 3);
      background: rgba(0, 168, 150, 0.12);
      border: 1.5px dashed #00a896;
      color: #007769;
    }

    .callout-mult {
      width: 100%;
      background: rgba(30, 41, 69, 0.08);
      border: 1.5px solid #1e2945;
      color: #1e2945;
    }

    /* State highlight styles */
    .mode-additive .seg-extra {
      background: #028f80;
    }

    .mode-mult .segment {
      box-shadow: inset 0 0 0 1px rgba(255,255,255,0.3);
    }

    .mode-mult .segment-tag {
      opacity: 1;
    }
  </style>
</head>
<body>

  <div class="controls">
    <button class="btn active" id="btnMult">Multiplicative (×3)</button>
    <button class="btn" id="btnAdd">Additive (+4 ft)</button>
  </div>

  <div class="diagram-area" id="diagram">
    
    <div class="rope-row">
      <div class="rope-meta">
        <span class="rope-label">Your Rope</span>
        <span class="rope-len">6 ft</span>
      </div>
      <div class="bar-container">
        <div class="rope-your">
          <div class="segment">
            <span>2 ft</span>
          </div>
          <div class="segment seg-extra">
            <span>2 ft</span>
          </div>
          <div class="segment seg-extra">
            <span>2 ft</span>
          </div>
        </div>
      </div>
    </div>

    
    <div class="rope-row">
      <div class="rope-meta">
        <span class="rope-label">Friend's Rope</span>
        <span class="rope-len">2 ft</span>
      </div>
      <div class="rope-friend-wrap">
        <div class="rope-friend">
          <span>2 ft</span>
        </div>
      </div>
    </div>

    
    <div class="bracket-layer">
      <div class="callout callout-mult active" id="calloutMult">
        3 × as long (3 groups of 2 ft)
      </div>
      <div class="callout callout-additive" id="calloutAdd">
        +4 ft longer
      </div>
    </div>
  </div>

  <script>
    const btnMult = document.getElementById('btnMult');
    const btnAdd = document.getElementById('btnAdd');
    const diagram = document.getElementById('diagram');
    const calloutMult = document.getElementById('calloutMult');
    const calloutAdd = document.getElementById('calloutAdd');

    function setMode(mode) {
      if (mode === 'mult') {
        btnMult.classList.add('active');
        btnAdd.classList.remove('active');
        diagram.classList.add('mode-mult');
        diagram.classList.remove('mode-additive');
        calloutMult.classList.add('active');
        calloutAdd.classList.remove('active');
      } else {
        btnAdd.classList.add('active');
        btnMult.classList.remove('active');
        diagram.classList.add('mode-additive');
        diagram.classList.remove('mode-mult');
        calloutAdd.classList.add('active');
        calloutMult.classList.remove('active');
      }
    }

    btnMult.addEventListener('click', () => setMode('mult'));
    btnAdd.addEventListener('click', () => setMode('add'));

    // Initialize default mode
    setMode('mult');
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 16px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
    }

    .main-grid {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 16px;
      width: 100%;
      max-width: 600px;
    }

    @media (max-width: 480px) {
      .main-grid {
        grid-template-columns: 1fr;
        gap: 12px;
      }
    }

    /* Panel Card */
    .panel {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 12px;
      padding: 14px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .panel-title {
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.05em;
      text-transform: uppercase;
      color: #6b7280;
      margin-bottom: 8px;
    }

    /* Formats Section */
    .format-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 6px 10px;
      margin-bottom: 6px;
      background: #f8f9fa;
      border-radius: 8px;
      font-size: 15px;
      font-weight: 600;
    }
    .format-row:last-child {
      margin-bottom: 0;
    }

    .format-orig {
      color: #6b7280;
    }
    .arrow {
      color: #0077b6;
      font-size: 14px;
    }
    .format-simp {
      color: #1e2945;
      font-weight: 700;
    }

    /* Tape Diagram Section */
    .tape-group {
      margin-bottom: 12px;
    }
    .tape-label {
      display: flex;
      justify-content: space-between;
      font-size: 12px;
      font-weight: 700;
      margin-bottom: 4px;
    }
    .tape-label-a { color: #0077b6; }
    .tape-label-b { color: #d97706; }

    .tape-bar {
      display: flex;
      gap: 3px;
      height: 32px;
      width: 100%;
    }
    .unit-box {
      flex: 1;
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 12px;
      font-weight: 700;
      color: #ffffff;
      transition: transform 0.2s ease, opacity 0.2s ease;
    }
    .box-blue {
      background: #0077b6;
    }
    .box-orange {
      background: #d97706;
    }

    .tape-bar-single {
      width: calc((100% - 6px) / 3);
    }

    /* Callout */
    .callout {
      background: #eff6ff;
      border: 1px solid #bfdbfe;
      border-radius: 8px;
      padding: 8px 10px;
      text-align: center;
      font-size: 13px;
      font-weight: 700;
      color: #0077b6;
    }

    /* Interactive toggle */
    .controls {
      display: flex;
      gap: 6px;
      margin-top: 12px;
      width: 100%;
      max-width: 600px;
    }
    .toggle-btn {
      flex: 1;
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #475569;
      padding: 8px;
      border-radius: 8px;
      font-size: 12px;
      font-weight: 700;
      cursor: pointer;
      text-align: center;
      transition: background 0.15s, color 0.15s;
    }
    .toggle-btn.active {
      background: #0077b6;
      border-color: #0077b6;
      color: #ffffff;
    }
  </style>
</head>
<body>

  <div class="main-grid">
    
    <div class="panel">
      <div class="panel-title">3 Representations</div>
      
      <div class="format-row">
        <span class="format-orig" id="f1-orig">6 to 2</span>
        <span class="arrow">→</span>
        <span class="format-simp" id="f1-simp">3 to 1</span>
      </div>

      <div class="format-row">
        <span class="format-orig" id="f2-orig">6 : 2</span>
        <span class="arrow">→</span>
        <span class="format-simp" id="f2-simp">3 : 1</span>
      </div>

      <div class="format-row">
        <span class="format-orig" id="f3-orig">6 / 2</span>
        <span class="arrow">→</span>
        <span class="format-simp" id="f3-simp">3 / 1</span>
      </div>
    </div>

    
    <div class="panel">
      <div class="panel-title">Tape Diagram</div>
      
      <div class="tape-group">
        <div class="tape-label">
          <span class="tape-label-a">Rope A</span>
          <span id="len-a">6 ft</span>
        </div>
        <div class="tape-bar">
          <div class="unit-box box-blue" id="box-a1">2 ft</div>
          <div class="unit-box box-blue" id="box-a2">2 ft</div>
          <div class="unit-box box-blue" id="box-a3">2 ft</div>
        </div>
      </div>

      <div class="tape-group">
        <div class="tape-label">
          <span class="tape-label-b">Rope B</span>
          <span id="len-b">2 ft</span>
        </div>
        <div class="tape-bar tape-bar-single">
          <div class="unit-box box-orange" id="box-b1">2 ft</div>
        </div>
      </div>

      <div class="callout" id="callout-text">
        Quantity A is <b>3 times</b> Quantity B
      </div>
    </div>
  </div>

  <div class="controls">
    <button class="toggle-btn active" id="btn-total" onclick="setMode('total')">Original (6 ft : 2 ft)</button>
    <button class="toggle-btn" id="btn-unit" onclick="setMode('unit')">Simplified (3 : 1)</button>
  </div>

  <script>
    function setMode(mode) {
      const isTotal = mode === 'total';
      
      document.getElementById('btn-total').classList.toggle('active', isTotal);
      document.getElementById('btn-unit').classList.toggle('active', !isTotal);

      document.getElementById('box-a1').textContent = isTotal ? '2 ft' : '1 unit';
      document.getElementById('box-a2').textContent = isTotal ? '2 ft' : '1 unit';
      document.getElementById('box-a3').textContent = isTotal ? '2 ft' : '1 unit';
      document.getElementById('box-b1').textContent = isTotal ? '2 ft' : '1 unit';

      document.getElementById('len-a').textContent = isTotal ? '6 ft' : '3 units';
      document.getElementById('len-b').textContent = isTotal ? '2 ft' : '1 unit';
    }
  </script>
</body>
</html>

111.26(b)(4)(C)

Aligned learning resources

Related diagrams