<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 10px 12px;
      margin: 0;
    }

    .main-wrap {
      width: 100%;
      max-width: 480px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    /* Step Navigation */
    .nav-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 8px;
    }

    .step-btn-group {
      display: flex;
      gap: 6px;
      flex: 1;
    }

    .step-btn {
      flex: 1;
      padding: 7px 4px;
      border: 1px solid #e2e8f0;
      background: #f8fafc;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      cursor: pointer;
      text-align: center;
      transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
    }

    .step-btn:hover {
      background: #f1f5f9;
      color: #0f172a;
    }

    .step-btn.active {
      background: #ffffff;
      color: #0284c7;
      border-color: #0284c7;
      box-shadow: 0 0 0 1px #0284c7;
    }

    .play-btn {
      padding: 7px 12px;
      border: 1px solid #e2e8f0;
      background: #ffffff;
      border-radius: 6px;
      font-size: 13px;
      cursor: pointer;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: background-color 0.2s ease;
    }

    .play-btn:hover {
      background: #f8fafc;
    }

    /* Ledger List */
    .ledger-list {
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    /* Rows */
    .entry-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 8px 12px;
      border-radius: 6px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
    }

    .entry-label {
      font-size: 13px;
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .entry-amt {
      font-size: 14px;
      font-family: ui-monospace, monospace;
      font-weight: 700;
    }

    .neg { color: #dc2626; }
    .pos { color: #16a34a; }
    .navy { color: #0f172a; }

    /* Segmented Bar (2/5 supplies) */
    .fraction-block {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: #f8fafc;
      border: 1px dashed #cbd5e1;
      border-radius: 6px;
      padding: 8px 12px;
    }

    .fraction-block.visible {
      display: flex;
    }

    .fraction-header {
      display: flex;
      justify-content: space-between;
      font-size: 12px;
      font-weight: 600;
    }

    .seg-bar {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      gap: 4px;
      height: 18px;
      width: 100%;
    }

    .seg {
      border-radius: 3px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 10px;
      font-weight: 700;
      color: #ffffff;
    }

    .seg-deduct {
      background: #ef4444;
    }

    .seg-keep {
      background: #22c55e;
    }

    /* Balance Callout */
    .balance-box {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 10px 12px;
      border-radius: 6px;
      background: #f1f5f9;
      border: 1.5px solid #cbd5e1;
      transition: background-color 0.25s ease, border-color 0.25s ease;
    }

    .balance-box.highlight-navy {
      background: #eff6ff;
      border-color: #3b82f6;
    }

    .balance-box.highlight-green {
      background: #ecfdf5;
      border-color: #10b981;
    }

    .bal-title {
      font-size: 13px;
      font-weight: 700;
    }

    .bal-val {
      font-size: 18px;
      font-family: ui-monospace, monospace;
      font-weight: 800;
    }
  </style>
</head>
<body>

  <div class="main-wrap">
    
    <div class="nav-bar">
      <div class="step-btn-group">
        <button class="step-btn active" id="btn-0">Step 1</button>
        <button class="step-btn" id="btn-1">Step 2</button>
        <button class="step-btn" id="btn-2">Step 3</button>
      </div>
      <button class="play-btn" id="playBtn" aria-label="Play or Pause">⏸</button>
    </div>

    
    <div class="ledger-list">
      
      
      <div class="entry-row" id="row-debt">
        <span class="entry-label">Debt</span>
        <span class="entry-amt neg">-$14.50</span>
      </div>

      
      <div class="entry-row" id="row-dep" style="display: none;">
        <span class="entry-label">Deposit</span>
        <span class="entry-amt pos">+$82.00</span>
      </div>
      <div class="entry-row" id="row-fee" style="display: none;">
        <span class="entry-label">Fee</span>
        <span class="entry-amt neg">-$4.25</span>
      </div>

      
      <div class="fraction-block" id="block-supplies">
        <div class="fraction-header">
          <span>Supplies (2/5 = 40%)</span>
          <span class="neg">-$25.30</span>
        </div>
        <div class="seg-bar">
          <div class="seg seg-deduct">1/5</div>
          <div class="seg seg-deduct">2/5</div>
          <div class="seg seg-keep">3/5</div>
          <div class="seg seg-keep">4/5</div>
          <div class="seg seg-keep">5/5</div>
        </div>
      </div>

      
      <div class="balance-box" id="balanceBox">
        <span class="bal-title" id="balTitle">Starting Balance</span>
        <span class="bal-val neg" id="balVal">-$14.50</span>
      </div>

    </div>
  </div>

  <script>
    let currentStep = 0;
    let playing = true;
    let timer = null;

    const btn0 = document.getElementById('btn-0');
    const btn1 = document.getElementById('btn-1');
    const btn2 = document.getElementById('btn-2');
    const playBtn = document.getElementById('playBtn');

    const rowDebt = document.getElementById('row-debt');
    const rowDep = document.getElementById('row-dep');
    const rowFee = document.getElementById('row-fee');
    const blockSupplies = document.getElementById('block-supplies');
    const balanceBox = document.getElementById('balanceBox');
    const balTitle = document.getElementById('balTitle');
    const balVal = document.getElementById('balVal');

    function updateStep(idx) {
      currentStep = idx;

      // Update buttons
      [btn0, btn1, btn2].forEach((b, i) => {
        b.classList.toggle('active', i === currentStep);
      });

      // Render Step States
      if (currentStep === 0) {
        rowDep.style.display = 'none';
        rowFee.style.display = 'none';
        blockSupplies.classList.remove('visible');

        balanceBox.className = 'balance-box';
        balTitle.textContent = 'Initial Debt';
        balVal.textContent = '-$14.50';
        balVal.className = 'bal-val neg';
      } 
      else if (currentStep === 1) {
        rowDep.style.display = 'flex';
        rowFee.style.display = 'flex';
        blockSupplies.classList.remove('visible');

        balanceBox.className = 'balance-box highlight-navy';
        balTitle.textContent = 'Intermediate Total';
        balVal.textContent = '+$63.25';
        balVal.className = 'bal-val navy';
      } 
      else if (currentStep === 2) {
        rowDep.style.display = 'flex';
        rowFee.style.display = 'flex';
        blockSupplies.classList.add('visible');

        balanceBox.className = 'balance-box highlight-green';
        balTitle.textContent = 'Final Balance';
        balVal.textContent = '+$37.95';
        balVal.className = 'bal-val pos';
      }
    }

    function nextStep() {
      currentStep = (currentStep + 1) % 3;
      updateStep(currentStep);
    }

    function startTimer() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 3500);
      playing = true;
      playBtn.textContent = '⏸';
    }

    function stopTimer() {
      if (timer) clearInterval(timer);
      timer = null;
      playing = false;
      playBtn.textContent = '▶';
    }

    playBtn.onclick = () => {
      if (playing) {
        stopTimer();
      } else {
        startTimer();
      }
    };

    [btn0, btn1, btn2].forEach((btn, i) => {
      btn.onclick = () => {
        stopTimer();
        updateStep(i);
      };
    });

    // Start auto cycle
    startTimer();
  </script>
</body>
</html>

Multi-Step Problems with Rational Numbers

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <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;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 10px 12px;
      min-height: 100vh;
      box-sizing: border-box;
    }

    .container {
      display: flex;
      flex-direction: column;
      align-items: center;
      width: 100%;
      max-width: 540px;
    }

    .main-layout {
      display: flex;
      flex-direction: row;
      align-items: center;
      justify-content: center;
      gap: 16px;
      width: 100%;
    }

    /* Thermometer Container */
    .thermo-container {
      position: relative;
      width: 135px;
      height: 310px;
      display: flex;
      justify-content: center;
      flex-shrink: 0;
    }

    .thermo-svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Math Panel */
    .math-panel {
      flex: 1;
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 12px;
      padding: 14px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
      min-width: 190px;
    }

    .step-card {
      padding: 9px 12px;
      border-radius: 8px;
      background: #f8f9fa;
      border: 1px solid #e2e8f0;
      transition: all 0.3s ease;
      cursor: pointer;
    }

    .step-card.active {
      background: #f0f9ff;
      border-color: #0284c7;
      box-shadow: 0 2px 6px rgba(2,132,199,0.12);
    }

    .step-label {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #475569;
      margin-bottom: 3px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .step-card.active .step-label {
      color: #0284c7;
    }

    .step-math {
      font-size: 14px;
      color: #334155;
      font-weight: 600;
      line-height: 1.35;
    }

    .step-card.active .step-math {
      color: #1e2945;
      font-weight: 700;
    }

    .frac {
      display: inline-flex;
      flex-direction: column;
      vertical-align: middle;
      text-align: center;
      font-size: 0.85em;
      line-height: 1;
      margin: 0 2px;
    }
    .frac > .num {
      border-bottom: 1px solid currentColor;
      padding: 0 1px;
    }
    .frac > .denom {
      padding: 0 1px;
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 10px;
      margin-top: 12px;
    }

    .btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      padding: 5px 14px;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, border-color 0.2s;
    }

    .btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .dots {
      display: flex;
      gap: 6px;
      margin-left: 4px;
    }

    .dot {
      width: 9px;
      height: 9px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: background 0.3s;
    }

    .dot.active {
      background: #0284c7;
    }

    /* Dynamic SVG elements */
    .mercury-drop {
      transition: height 0.5s ease, y 0.5s ease;
    }

    .arrow-path, .arrow-head, .marker-end {
      transition: opacity 0.35s ease;
    }

    @media (max-width: 440px) {
      .main-layout {
        gap: 8px;
      }
      .thermo-container {
        width: 115px;
        height: 290px;
      }
      .math-panel {
        padding: 10px;
        gap: 8px;
        min-width: 175px;
      }
      .step-card {
        padding: 7px 9px;
      }
      .step-math {
        font-size: 13px;
      }
    }
  </style>
</head>
<body>

  <div class="container">
    <div class="main-layout">
      
      <div class="thermo-container">
        <svg class="thermo-svg" viewBox="0 0 145 320">
          <defs>
            <linearGradient id="mercuryGrad" x1="0" y1="0" x2="0" y2="1">
              <stop offset="0%" stop-color="#38bdf8" />
              <stop offset="1%" stop-color="#0284c7" />
            </linearGradient>
          </defs>

          
          
          <rect x="52" y="15" width="16" height="260" rx="8" fill="#e2e8f0" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="60" cy="280" r="16" fill="#0284c7" />

          
          
          <line x1="42" y1="25" x2="52" y2="25" stroke="#475569" stroke-width="1.5" />
          <text x="38" y="29" font-size="12" font-weight="700" fill="#1e2945" text-anchor="end">0°F</text>

          
          <line x1="46" y1="65" x2="52" y2="65" stroke="#94a3b8" stroke-width="1" />

          
          <line x1="44" y1="105" x2="52" y2="105" stroke="#94a3b8" stroke-width="1" />
          <text x="38" y="109" font-size="11" font-weight="600" fill="#475569" text-anchor="end">-4°</text>

          
          <line x1="46" y1="145" x2="52" y2="145" stroke="#94a3b8" stroke-width="1" />

          
          <line x1="44" y1="185" x2="52" y2="185" stroke="#94a3b8" stroke-width="1" />
          <text x="38" y="189" font-size="11" font-weight="600" fill="#475569" text-anchor="end">-8°</text>

          
          <line x1="46" y1="225" x2="52" y2="225" stroke="#94a3b8" stroke-width="1" />

          
          <line x1="42" y1="265" x2="52" y2="265" stroke="#475569" stroke-width="1.5" />
          <text x="38" y="269" font-size="11" font-weight="600" fill="#475569" text-anchor="end">-12°</text>

          
          
          
          
          <rect id="mercury" class="mercury-drop" x="55" y="75" width="10" height="210" fill="url(#mercuryGrad)" rx="5" />

          
          <g id="startMarker">
            <line x1="68" y1="75" x2="86" y2="75" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="2,2" />
            <circle cx="68" cy="75" r="3" fill="#0284c7" />
            <text x="90" y="79" font-size="11.5" font-weight="700" fill="#0284c7">-2.5°F</text>
          </g>

          
          <g id="arrowGroup" opacity="0">
            <line class="arrow-path" x1="82" y1="83" x2="82" y2="225" stroke="#0284c7" stroke-width="2.5" />
            <polygon class="arrow-head" points="82,231 77,221 87,221" fill="#0284c7" />
            <rect x="86" y="142" width="54" height="20" rx="4" fill="#ffffff" stroke="#0284c7" stroke-width="1" />
            <text x="113" y="156" font-size="11" font-weight="700" fill="#0284c7" text-anchor="middle">-7.875°</text>
          </g>

          
          <g id="endMarker" class="marker-end" opacity="0">
            <line x1="68" y1="232.5" x2="78" y2="232.5" stroke="#1e2945" stroke-width="1.5" stroke-dasharray="2,2" />
            <circle cx="68" cy="232.5" r="3" fill="#1e2945" />
            <text x="84" y="236" font-size="11.5" font-weight="700" fill="#1e2945">-10.375°F</text>
          </g>
        </svg>
      </div>

      
      <div class="math-panel">
        
        <div id="card0" class="step-card active">
          <div class="step-label">
            <span>1. Initial Temp</span>
            <span class="status-indicator">●</span>
          </div>
          <div class="step-math">
            −2.5°F = −2<span class="frac"><span class="num">1</span><span class="denom">2</span></span>°F
          </div>
        </div>

        
        <div id="card1" class="step-card">
          <div class="step-label">
            <span>2. Temperature Drop</span>
            <span class="status-indicator">●</span>
          </div>
          <div class="step-math">
            4.5 × (−1.75°F) = −7.875°F
          </div>
        </div>

        
        <div id="card2" class="step-card">
          <div class="step-label">
            <span>3. Final Temp</span>
            <span class="status-indicator">●</span>
          </div>
          <div class="step-math">
            −2.5 + (−7.875) = −10.375°F
            <div style="font-size: 0.9em; font-weight: normal; margin-top: 2px; color: #475569;">
              (= −10<span class="frac"><span class="num">3</span><span class="denom">8</span></span>°F)
            </div>
          </div>
        </div>
      </div>
    </div>

    
    <div class="controls">
      <button class="btn" id="prevBtn" aria-label="Previous step">‹</button>
      <button class="btn" id="playBtn">Next Step ›</button>
      <button class="btn" id="nextBtn" aria-label="Next step">›</button>
      <div class="dots">
        <div class="dot active" data-step="0" title="Step 1"></div>
        <div class="dot" data-step="1" title="Step 2"></div>
        <div class="dot" data-step="2" title="Step 3"></div>
      </div>
    </div>
  </div>

  <script>
    let currentStep = 0;
    const totalSteps = 3;

    const mercury = document.getElementById('mercury');
    const arrowGroup = document.getElementById('arrowGroup');
    const endMarker = document.getElementById('endMarker');
    const cards = [document.getElementById('card0'), document.getElementById('card1'), document.getElementById('card2')];
    const dots = document.querySelectorAll('.dot');
    const playBtn = document.getElementById('playBtn');

    function updateStep(step) {
      currentStep = step;

      // Update Card highlights
      cards.forEach((card, i) => {
        if (i === step) {
          card.classList.add('active');
        } else {
          card.classList.remove('active');
        }
      });

      // Update Dots
      dots.forEach((dot, i) => {
        dot.classList.toggle('active', i === step);
      });

      // Update SVG elements based on step
      if (step === 0) {
        mercury.setAttribute('y', '75');
        mercury.setAttribute('height', '210');
        arrowGroup.setAttribute('opacity', '0');
        endMarker.setAttribute('opacity', '0');
        playBtn.textContent = 'Next Step ›';
      } else if (step === 1) {
        mercury.setAttribute('y', '75');
        mercury.setAttribute('height', '210');
        arrowGroup.setAttribute('opacity', '1');
        endMarker.setAttribute('opacity', '0');
        playBtn.textContent = 'Next Step ›';
      } else if (step === 2) {
        mercury.setAttribute('y', '232.5');
        mercury.setAttribute('height', '52.5');
        arrowGroup.setAttribute('opacity', '1');
        endMarker.setAttribute('opacity', '1');
        playBtn.textContent = '↺ Restart';
      }
    }

    document.getElementById('nextBtn').addEventListener('click', () => {
      updateStep((currentStep + 1) % totalSteps);
    });

    document.getElementById('prevBtn').addEventListener('click', () => {
      updateStep((currentStep - 1 + totalSteps) % totalSteps);
    });

    playBtn.addEventListener('click', () => {
      updateStep((currentStep + 1) % totalSteps);
    });

    dots.forEach((dot) => {
      dot.addEventListener('click', () => {
        updateStep(parseInt(dot.getAttribute('data-step'), 10));
      });
    });

    cards.forEach((card, index) => {
      card.addEventListener('click', () => {
        updateStep(index);
      });
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Rational Numbers</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      width: 100%;
      min-height: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
    }

    .diagram {
      width: 100%;
      max-width: 540px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 0;
    }

    /* Top Cards Grid */
    .cards-row {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
    }

    .type-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 4px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      text-align: center;
      cursor: pointer;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
      user-select: none;
      min-height: 84px;
    }

    .type-card:hover {
      border-color: #93c5fd;
      box-shadow: 0 3px 10px rgba(59, 130, 246, 0.1);
    }

    .type-card.active {
      border-color: #3b82f6;
      background: #eff6ff;
      box-shadow: 0 4px 12px rgba(59, 130, 246, 0.18);
    }

    .card-title {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 4px;
      line-height: 1.2;
    }

    .card-subtitle {
      font-size: 10.5px;
      color: #64748b;
      margin-bottom: 6px;
    }

    .card-math {
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      background: #ffffff;
      border: 2px solid #3b82f6;
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</head>
<body>
  <div class="diagram">
    
    <div class="cards-row">
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        <div class="card-title">Fractions</div>
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          <span class="frac">
            <span class="num">3</span>
            <span class="denom">4</span>
          </span>
        </div>
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        <div class="card-title">Terminating</div>
        <div class="card-subtitle">Ends cleanly</div>
        <div class="card-math">
          <span>2.75 = </span>
          <span class="frac">
            <span class="num">11</span>
            <span class="denom">4</span>
          </span>
        </div>
      </div>

      <div class="type-card" id="card-2" onclick="selectType(2)" role="button" tabindex="0" aria-label="Repeating decimals example">
        <div class="card-title">Repeating</div>
        <div class="card-subtitle">Pattern repeats</div>
        <div class="card-math">
          <span>0.<span class="overline">3</span> = </span>
          <span class="frac">
            <span class="num">1</span>
            <span class="denom">3</span>
          </span>
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      <div class="hub-header">
        <span class="hub-badge">Definition</span>
        <span class="hub-title">Rational Numbers</span>
      </div>

      <div class="hub-formula-box">
        <span>Any number written as</span>
        <span class="frac">
          <span class="num">a</span>
          <span class="denom">b</span>
        </span>
        <span class="hub-condition">where <em>a</em>, <em>b</em> are integers and <em>b</em> ≠ 0</span>
      </div>

      <div class="hub-explanation" id="hub-desc">
        Click any card above to see how it converts to an a/b ratio.
      </div>
    </div>
  </div>

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      "2.75 terminates at hundredths: 275/100 simplifies directly to 11/4.",
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</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;
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  </style>
</head>
<body>

  <div class="diagram-area">
    
    <div class="bracket-row">
      <div class="top-bracket">
        <div class="bracket-label">Total: 8.5 ft (8 ½ ft)</div>
        <div class="bracket-line"></div>
      </div>
    </div>

    
    <div class="beam-container">
      
      <div class="cut-piece" id="cutPiece">
        <div class="val-main">2.25 ft</div>
        <div class="val-sub">2 ¼ ft (Cut)</div>
      </div>

      
      <div class="remaining-section" id="remSection">
        <div class="block block-1">
          <div class="val-main">25/12 ft</div>
          <div class="val-sub">2 ¹/₁₂ ft (≈2.08 ft)</div>
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          <div class="val-main">25/12 ft</div>
          <div class="val-sub">2 ¹/₁₂ ft (≈2.08 ft)</div>
        </div>
        <div class="block block-3">
          <div class="val-main">25/12 ft</div>
          <div class="val-sub">2 ¹/₁₂ ft (≈2.08 ft)</div>
        </div>
      </div>
    </div>

    
    <div class="calc-row">
      <div class="calc-pill" id="card1">
        <div class="calc-title">1. Cut Piece</div>
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        <div class="calc-title">2. Fraction Form</div>
        <div class="calc-math">6.25 = 25/4 ft</div>
      </div>
      <div class="calc-pill" id="card3">
        <div class="calc-title">3. Divide into 3</div>
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      </div>
    </div>

    
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      <button class="step-btn" onclick="setStep(1)">Cut: 2.25 ft</button>
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  </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">
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</head>
<body>

  <div class="top-bar">
    <button class="pill-btn active" onclick="selectType('all')">All Strategies</button>
    <button class="pill-btn" onclick="selectType('term')">0.25 + ¾</button>
    <button class="pill-btn" onclick="selectType('rep')">⅓ + 0.5</button>
  </div>

  <div class="tree-container">
    <div class="root-card" id="rootBox">
      🔍 Look at your numbers
    </div>

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      <div class="branch-card branch-left" id="leftCard">
        <div class="badge badge-blue">Terminating</div>
        <div class="examples">0.25 • 1.5 • ¾</div>
        <div class="action-title" style="color: #2563eb;">Convert to Decimals</div>
        <div class="reason">Faster for money & metric</div>
      </div>

      
      <div class="branch-card branch-right" id="rightCard">
        <div class="badge badge-green">Repeating</div>
        <div class="examples">⅓ • ⅔ • 0.33...</div>
        <div class="action-title" style="color: #059669;">Convert to Fractions</div>
        <div class="reason">Preserves exact precision</div>
      </div>
    </div>
  </div>

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<head>
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  <meta name="aspect-ratio" content="4:3">
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      background: #ffffff;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    .main-wrap {
      width: 100%;
      max-width: 600px;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    /* Equation Header */
    .eq-header {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 8px;
      font-size: 18px;
      font-weight: 700;
    }
    .pos-val { color: #0284c7; background: #e0f2fe; padding: 3px 8px; border-radius: 6px; }
    .neg-val { color: #ea580c; background: #ffedd5; padding: 3px 8px; border-radius: 6px; }
    .res-val { color: #dc2626; background: #fee2e2; padding: 3px 8px; border-radius: 6px; }

    /* SVG container */
    .svg-container {
      width: 100%;
      position: relative;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    /* Step control bar */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      flex-wrap: wrap;
    }
    .btn {
      appearance: none;
      border: 1px solid #cbd5e1;
      background: #f8fafc;
      color: #1e2945;
      font-size: 13px;
      font-weight: 600;
      padding: 6px 12px;
      border-radius: 6px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }
    .btn:active { background: #e2e8f0; }
    .btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }

    /* Result summary card */
    .result-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: space-around;
      gap: 8px;
      font-size: 13px;
      font-weight: 600;
      flex-wrap: wrap;
    }
    .step-text {
      color: #475569;
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .step-tag {
      font-size: 11px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      padding: 2px 6px;
      border-radius: 4px;
      background: #e2e8f0;
      color: #334155;
    }

    /* Animation transitions */
    .anim-vec {
      transition: stroke-dashoffset 0.8s ease, opacity 0.4s ease;
    }
    .fade-item {
      transition: opacity 0.4s ease, transform 0.4s ease;
    }
  </style>
</head>
<body>

  <div class="main-wrap">
    
    <div class="eq-header">
      <span class="pos-val">(+5.2)</span>
      <span>+</span>
      <span class="neg-val">(-7.8)</span>
      <span>=</span>
      <span class="res-val" id="eqResult">-2.6</span>
    </div>

    
    <div class="svg-container">
      <svg viewBox="0 0 580 220" id="diagramSvg">
        <defs>
          
          <marker id="arrow-blue" markerWidth="8" markerHeight="8" refX="7" refY="4" orient="auto">
            <polygon points="0 0, 8 4, 0 8" fill="#0284c7" />
          </marker>
          <marker id="arrow-coral" markerWidth="8" markerHeight="8" refX="7" refY="4" orient="auto">
            <polygon points="0 0, 8 4, 0 8" fill="#ea580c" />
          </marker>
          <marker id="arrow-res" markerWidth="7" markerHeight="7" refX="6" refY="3.5" orient="auto">
            <polygon points="0 0, 7 3.5, 0 7" fill="#dc2626" />
          </marker>

          
          <pattern id="diagonalHatch" width="8" height="8" patternTransform="rotate(45 0 0)" patternUnits="userSpaceOnUse">
            <line x1="0" y1="0" x2="0" y2="8" stroke="#94a3b8" stroke-width="2" opacity="0.4" />
          </pattern>
        </defs>

        
        

        
        <g id="cancelZone" class="fade-item" opacity="0">
          <rect x="240" y="45" width="260" height="75" fill="url(#diagonalHatch)" rx="4" />
          <rect x="240" y="45" width="260" height="75" fill="#f1f5f9" fill-opacity="0.6" rx="4" />
          <text x="370" y="85" text-anchor="middle" font-size="12" font-weight="700" fill="#64748b">
            Opposites Cancel: 5.2
          </text>
        </g>

        
        <g id="remainderZone" class="fade-item" opacity="0">
          <rect x="110" y="145" width="130" height="24" fill="#fee2e2" rx="4" stroke="#fca5a5" stroke-width="1" stroke-dasharray="3,3" />
          <text x="175" y="161" text-anchor="middle" font-size="11" font-weight="700" fill="#dc2626">
            Remainder: 2.6
          </text>
        </g>

        
        <line x1="20" y1="130" x2="560" y2="130" stroke="#64748b" stroke-width="2" stroke-linecap="round" />
        
        
        <polygon points="18,130 26,126 26,134" fill="#64748b" />
        <polygon points="562,130 554,126 554,134" fill="#64748b" />

        
        
        <g id="ticks" stroke="#94a3b8" stroke-width="1.5">
          <line x1="40" y1="124" x2="40" y2="136" />
          <line x1="90" y1="126" x2="90" y2="134" />
          <line x1="140" y1="126" x2="140" y2="134" />
          <line x1="190" y1="126" x2="190" y2="134" />
          <line x1="240" y1="120" x2="240" y2="140" stroke="#1e2945" stroke-width="2.5" />
          <line x1="290" y1="126" x2="290" y2="134" />
          <line x1="340" y1="126" x2="340" y2="134" />
          <line x1="390" y1="126" x2="390" y2="134" />
          <line x1="440" y1="126" x2="440" y2="134" />
          <line x1="490" y1="126" x2="490" y2="134" />
          <line x1="540" y1="124" x2="540" y2="136" />
        </g>

        
        <g font-size="11" fill="#64748b" text-anchor="middle" font-weight="500">
          <text x="40" y="146">-4</text>
          <text x="90" y="146">-3</text>
          <text x="140" y="146">-2</text>
          <text x="190" y="146">-1</text>
          <text x="240" y="148" fill="#1e2945" font-weight="700">0</text>
          <text x="290" y="146">+1</text>
          <text x="340" y="146">+2</text>
          <text x="390" y="146">+3</text>
          <text x="440" y="146">+4</text>
          <text x="490" y="146">+5</text>
          <text x="540" y="146">+6</text>
        </g>

        
        <line id="drop0" x1="240" y1="95" x2="240" y2="130" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" />
        <line id="drop52" x1="500" y1="40" x2="500" y2="130" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="3,3" class="fade-item" opacity="0" />
        <line id="dropFinal" x1="110" y1="40" x2="110" y2="185" stroke="#dc2626" stroke-width="1.5" stroke-dasharray="3,3" class="fade-item" opacity="0" />

        
        <g id="vector1" class="fade-item" opacity="0">
          <line x1="240" y1="105" x2="494" y2="105" stroke="#0284c7" stroke-width="4" stroke-linecap="round" marker-end="url(#arrow-blue)" />
          <circle cx="240" cy="105" r="4" fill="#0284c7" />
          <rect x="345" y="93" width="50" height="18" rx="4" fill="#e0f2fe" />
          <text x="370" y="106" text-anchor="middle" font-size="11" font-weight="700" fill="#0369a1">+5.2</text>
        </g>

        
        <g id="vector2" class="fade-item" opacity="0">
          <line x1="500" y1="55" x2="116" y2="55" stroke="#ea580c" stroke-width="4" stroke-linecap="round" marker-end="url(#arrow-coral)" />
          <circle cx="500" cy="55" r="4" fill="#ea580c" />
          <rect x="280" y="27" width="50" height="18" rx="4" fill="#ffedd5" />
          <text x="305" y="40" text-anchor="middle" font-size="11" font-weight="700" fill="#c2410c">-7.8</text>
        </g>

        
        <g id="finalPoint" class="fade-item" opacity="0">
          <circle cx="110" cy="130" r="5" fill="#dc2626" stroke="#ffffff" stroke-width="2" />
          <rect x="85" y="188" width="50" height="20" rx="4" fill="#dc2626" />
          <text x="110" y="202" text-anchor="middle" font-size="12" font-weight="700" fill="#ffffff">-2.6</text>
        </g>
      </svg>
    </div>

    
    <div class="result-card" id="cardSummary">
      <div class="step-text" id="stepDetail">
        <span class="step-tag">Step 1</span>
        <span>Start at 0, move <b>+5.2</b> to the right</span>
      </div>
    </div>

    
    <div class="controls">
      <button class="btn" id="btnPrev">← Back</button>
      <button class="btn active" id="btn1" onclick="setStep(0)">1: +5.2</button>
      <button class="btn" id="btn2" onclick="setStep(1)">2: -7.8</button>
      <button class="btn" id="btn3" onclick="setStep(2)">3: Cancel</button>
      <button class="btn" id="btn4" onclick="setStep(3)">4: Result</button>
      <button class="btn" id="btnNext">Next →</button>
      <button class="btn" id="btnPlay">⏸</button>
    </div>
  </div>

  <script>
    let currentStep = 0;
    let isPlaying = true;
    let timer = null;

    const stepData = [
      {
        tag: "Step 1",
        text: "Start at 0, move <b>+5.2</b> units right",
        v1: 1, v2: 0, cancel: 0, remainder: 0, final: 0, drop52: 1, dropF: 0
      },
      {
        tag: "Step 2",
        text: "From +5.2, move <b>-7.8</b> units left",
        v1: 1, v2: 1, cancel: 0, remainder: 0, final: 0, drop52: 1, dropF: 1
      },
      {
        tag: "Step 3",
        text: "Distance difference: <b>7.8 - 5.2 = 2.6</b>",
        v1: 1, v2: 1, cancel: 1, remainder: 1, final: 0, drop52: 1, dropF: 1
      },
      {
        tag: "Step 4",
        text: "Negative vector is longer → lands on <b>-2.6</b>",
        v1: 1, v2: 1, cancel: 1, remainder: 1, final: 1, drop52: 1, dropF: 1
      }
    ];

    function updateView() {
      const s = stepData[currentStep];

      // Update diagram elements opacity
      document.getElementById('vector1').style.opacity = s.v1;
      document.getElementById('vector2').style.opacity = s.v2;
      document.getElementById('cancelZone').style.opacity = s.cancel;
      document.getElementById('remainderZone').style.opacity = s.remainder;
      document.getElementById('finalPoint').style.opacity = s.final;
      document.getElementById('drop52').style.opacity = s.drop52;
      document.getElementById('dropFinal').style.opacity = s.dropF;

      // Update text
      document.getElementById('stepDetail').innerHTML = `
        <span class="step-tag">${s.tag}</span>
        <span>${s.text}</span>
      `;

      // Update buttons
      for (let i = 0; i < 4; i++) {
        document.getElementById(`btn${i+1}`).classList.toggle('active', i === currentStep);
      }
    }

    function setStep(idx) {
      currentStep = idx;
      updateView();
    }

    function nextStep() {
      currentStep = (currentStep + 1) % 4;
      updateView();
    }

    function prevStep() {
      currentStep = (currentStep - 1 + 4) % 4;
      updateView();
    }

    document.getElementById('btnNext').onclick = () => { nextStep(); pause(); };
    document.getElementById('btnPrev').onclick = () => { prevStep(); pause(); };

    const playBtn = document.getElementById('btnPlay');
    function pause() {
      isPlaying = false;
      playBtn.textContent = '▶';
      clearInterval(timer);
    }
    function play() {
      isPlaying = true;
      playBtn.textContent = '⏸';
      clearInterval(timer);
      timer = setInterval(nextStep, 3500);
    }

    playBtn.onclick = () => {
      if (isPlaying) pause();
      else { play(); }
    };

    // Initialize
    updateView();
    timer = setInterval(nextStep, 3500);
  </script>
</body>
</html>

Adding Rational Numbers with Same and Different Signs

<!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 {
      width: 100%;
      min-height: 100%;
      background: #ffffff;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px 8px;
    }

    .main-wrap {
      width: 100%;
      max-width: 620px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 12px;
    }

    /* Equation header */
    .equation-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 16px;
      font-weight: 700;
    }
    .pos-val {
      color: #16a34a;
      background: #f0fdf4;
      padding: 3px 8px;
      border-radius: 6px;
      border: 1px solid #bbf7d0;
    }
    .neg-val {
      color: #dc2626;
      background: #fef2f2;
      padding: 3px 8px;
      border-radius: 6px;
      border: 1px solid #fecaca;
    }
    .res-val {
      color: #b91c1c;
      background: #fee2e2;
      padding: 3px 8px;
      border-radius: 6px;
      border: 2px solid #ef4444;
      font-weight: 800;
    }

    /* Board layout */
    .board-container {
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      overflow-x: auto;
      padding: 4px 2px;
    }

    .zero-group {
      display: flex;
      flex-direction: column;
      align-items: center;
      border: 2px dashed #94a3b8;
      border-radius: 10px;
      padding: 8px 6px 6px;
      background: rgba(248, 250, 252, 0.9);
      position: relative;
      transition: opacity 0.3s ease, filter 0.3s ease;
    }

    .zero-label {
      font-size: 12px;
      font-weight: 700;
      color: #64748b;
      margin-bottom: 6px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      white-space: nowrap;
    }

    .grid-9 {
      display: grid;
      grid-template-columns: repeat(9, 1fr);
      gap: 4px;
    }

    .single-group {
      display: flex;
      flex-direction: column;
      align-items: center;
      border: 2px solid #ef4444;
      border-radius: 10px;
      padding: 8px 6px 6px;
      background: #fff5f5;
    }

    .rem-label {
      font-size: 12px;
      font-weight: 800;
      color: #dc2626;
      margin-bottom: 6px;
      white-space: nowrap;
    }

    .col-pair {
      display: flex;
      flex-direction: column;
      gap: 8px;
      align-items: center;
    }

    /* Individual fraction tile */
    .tile {
      width: 32px;
      height: 40px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      font-size: 10px;
      font-weight: 800;
      border-radius: 5px;
      user-select: none;
      transition: transform 0.3s ease, opacity 0.3s ease;
    }

    .tile-pos {
      background: #dcfce7;
      border: 1.5px solid #22c55e;
      color: #15803d;
    }

    .tile-neg {
      background: #fee2e2;
      border: 1.5px solid #ef4444;
      color: #b91c1c;
    }

    .frac-num {
      line-height: 1;
      border-bottom: 1.5px solid currentColor;
      padding: 0 1px 1px;
    }
    .frac-den {
      line-height: 1;
      padding-top: 1px;
    }

    .tile-empty {
      width: 32px;
      height: 40px;
      border: 1.5px dashed #cbd5e1;
      border-radius: 5px;
      background: transparent;
    }

    /* Cancel effect */
    .is-cancelled .tile {
      opacity: 0.25;
    }
    .is-cancelled .zero-label {
      color: #94a3b8;
      text-decoration: line-through;
    }
    .strike-line {
      position: absolute;
      top: 58%;
      left: 4%;
      width: 92%;
      height: 3px;
      background: #64748b;
      border-radius: 2px;
      opacity: 0;
      transition: opacity 0.3s ease;
      pointer-events: none;
    }
    .is-cancelled .strike-line {
      opacity: 0.8;
    }

    /* Interactive controls */
    .controls {
      display: flex;
      gap: 8px;
    }
    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #334155;
      padding: 6px 14px;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
    }
    .btn.active {
      background: #2563eb;
      color: #ffffff;
      border-color: #2563eb;
    }

    @media (max-width: 440px) {
      .tile, .tile-empty {
        width: 24px;
        height: 36px;
        font-size: 9px;
      }
      .zero-group, .single-group {
        padding: 6px 3px 4px;
      }
      .grid-9 {
        gap: 2px;
      }
      .zero-label, .rem-label {
        font-size: 10px;
      }
      .equation-bar {
        font-size: 14px;
      }
    }
  </style>
</head>
<body>

  <div class="main-wrap">
    
    <div class="equation-bar">
      <span class="pos-val">+9/12</span>
      <span>+</span>
      <span class="neg-val">−10/12</span>
      <span>=</span>
      <span class="res-val" id="resText">−1/12</span>
    </div>

    
    <div class="board-container">
      
      <div class="zero-group" id="zeroGroup">
        <div class="zero-label">9 Zero Pairs (Cancel to 0)</div>
        <div class="strike-line"></div>
        <div class="grid-9">
          
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
          <div class="col-pair">
            <div class="tile tile-pos"><span class="frac-num">+1</span><span class="frac-den">12</span></div>
            <div class="tile tile-neg"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
          </div>
        </div>
      </div>

      
      <div class="single-group">
        <div class="rem-label">Remaining: −1/12</div>
        <div class="col-pair">
          <div class="tile-empty"></div>
          <div class="tile tile-neg" style="box-shadow: 0 0 0 2px #ef4444;"><span class="frac-num">−1</span><span class="frac-den">12</span></div>
        </div>
      </div>
    </div>

    
    <div class="controls">
      <button class="btn active" id="btnPair" onclick="setMode(false)">Pairs</button>
      <button class="btn" id="btnCancel" onclick="setMode(true)">Cancel Out</button>
    </div>
  </div>

  <script>
    function setMode(cancelled) {
      const zg = document.getElementById('zeroGroup');
      const bP = document.getElementById('btnPair');
      const bC = document.getElementById('btnCancel');
      if (cancelled) {
        zg.classList.add('is-cancelled');
        bC.classList.add('active');
        bP.classList.remove('active');
      } else {
        zg.classList.remove('is-cancelled');
        bP.classList.add('active');
        bC.classList.remove('active');
      }
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #0f172a;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 12px 10px;
      gap: 10px;
      user-select: none;
    }

    .controls {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: center;
      gap: 8px;
      width: 100%;
      max-width: 540px;
    }

    .btn {
      background: #f1f5f9;
      border: 1.5px solid #cbd5e1;
      color: #1e293b;
      font-size: 14px;
      font-weight: 700;
      padding: 8px 16px;
      border-radius: 8px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      transition: background-color 0.15s, border-color 0.15s, color 0.15s, box-shadow 0.15s;
      min-height: 38px;
    }
    .btn:hover {
      background: #e2e8f0;
      border-color: #94a3b8;
    }
    .btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.35);
    }

    .stage {
      width: 100%;
      max-width: 600px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    .tick-label {
      font-size: 16px;
      font-weight: 700;
      fill: #334155;
      text-anchor: middle;
      font-family: inherit;
    }

    .origin-label {
      font-size: 18px;
      font-weight: 900;
      fill: #0f172a;
      text-anchor: middle;
      font-family: inherit;
    }

    .vec-label {
      font-size: 16px;
      font-weight: 800;
      text-anchor: middle;
      font-family: inherit;
    }

    .sub-label {
      font-size: 13px;
      font-weight: 700;
      text-anchor: middle;
      fill: #475569;
      font-family: inherit;
    }

    .vector-group {
      transition: opacity 0.35s ease;
    }

    .summary-card {
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 18px;
      font-size: 20px;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: center;
      min-height: 46px;
      width: 100%;
      max-width: 440px;
      text-align: center;
    }

    .val-blue {
      color: #0284c7;
      font-weight: 800;
    }

    .val-coral {
      color: #ea580c;
      font-weight: 800;
    }

    .val-zero {
      color: #0f172a;
      font-weight: 800;
    }

    @media (max-width: 480px) {
      .btn {
        font-size: 13px;
        padding: 6px 12px;
      }
      .summary-card {
        font-size: 18px;
        min-height: 42px;
        padding: 6px 12px;
      }
      .tick-label {
        font-size: 15px;
      }
    }
  </style>
</head>
<body>

  <div class="controls">
    <button class="btn" id="btn1" onclick="setStep(1)">Step 1: +3.5</button>
    <button class="btn" id="btn2" onclick="setStep(2)">Step 2: −3.5</button>
    <button class="btn" id="btnPlay" onclick="togglePlay()">▶ Auto</button>
  </div>

  <div class="stage">
    <svg viewBox="0 0 600 225" aria-label="Additive Inverse Number Line">
      <defs>
        <marker id="arrow-blue" viewBox="0 0 10 10" refX="7" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#0284c7" />
        </marker>
        <marker id="arrow-coral" viewBox="0 0 10 10" refX="7" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#ea580c" />
        </marker>
        <marker id="line-axis-left" viewBox="0 0 10 10" refX="2" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 8 1.5 L 0 5 L 8 8.5 z" fill="#475569" />
        </marker>
        <marker id="line-axis-right" viewBox="0 0 10 10" refX="8" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#475569" />
        </marker>
      </defs>

      
      <line x1="28" y1="170" x2="572" y2="170" stroke="#475569" stroke-width="3" marker-start="url(#line-axis-left)" marker-end="url(#line-axis-right)" />

      
      
      <line x1="50" y1="160" x2="50" y2="180" stroke="#475569" stroke-width="2.5" />
      <text x="50" y="202" class="tick-label">−4</text>

      
      <line x1="112.5" y1="162" x2="112.5" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="112.5" y="202" class="tick-label">−3</text>

      
      <line x1="175" y1="162" x2="175" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="175" y="202" class="tick-label">−2</text>

      
      <line x1="237.5" y1="162" x2="237.5" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="237.5" y="202" class="tick-label">−1</text>

      
      <line x1="300" y1="158" x2="300" y2="182" stroke="#0f172a" stroke-width="3" />
      <text x="300" y="203" class="origin-label">0</text>

      
      <line x1="362.5" y1="162" x2="362.5" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="362.5" y="202" class="tick-label">+1</text>

      
      <line x1="425" y1="162" x2="425" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="425" y="202" class="tick-label">+2</text>

      
      <line x1="487.5" y1="162" x2="487.5" y2="178" stroke="#64748b" stroke-width="2" />
      <text x="487.5" y="202" class="tick-label">+3</text>

      
      <line x1="518.75" y1="164" x2="518.75" y2="176" stroke="#0284c7" stroke-width="2" stroke-dasharray="2 2" />

      
      <line x1="550" y1="160" x2="550" y2="180" stroke="#475569" stroke-width="2.5" />
      <text x="550" y="202" class="tick-label">+4</text>

      
      <line id="guide-turn" x1="518.75" y1="46" x2="518.75" y2="164" stroke="#94a3b8" stroke-width="1.75" stroke-dasharray="3 3" opacity="0" />

      
      <line id="guide-zero" x1="300" y1="46" x2="300" y2="164" stroke="#94a3b8" stroke-width="1.75" stroke-dasharray="3 3" opacity="0" />

      
      <g id="vec1" class="vector-group" opacity="0">
        <line x1="300" y1="112" x2="512" y2="112" stroke="#0284c7" stroke-width="3.5" marker-end="url(#arrow-blue)" />
        <circle cx="300" cy="112" r="5" fill="#0284c7" />
        <text x="409.375" y="98" class="vec-label" fill="#0284c7">+3.5</text>
        <text x="409.375" y="130" class="sub-label">Magnitude: 3.5</text>
      </g>

      
      <g id="vec2" class="vector-group" opacity="0">
        <line x1="518.75" y1="48" x2="307" y2="48" stroke="#ea580c" stroke-width="3.5" marker-end="url(#arrow-coral)" />
        <circle cx="518.75" cy="48" r="5" fill="#ea580c" />
        <circle cx="300" cy="170" r="5.5" fill="#ea580c" />
        <text x="409.375" y="34" class="vec-label" fill="#ea580c">−3.5</text>
        <text x="409.375" y="68" class="sub-label">Magnitude: 3.5</text>
      </g>
    </svg>
  </div>

  <div class="summary-card" id="mathCard" aria-live="polite"></div>

  <script>
    let currentStep = 1;
    let autoPlayTimer = null;

    function renderMath(step) {
      const card = document.getElementById('mathCard');
      if (step === 1) {
        card.innerHTML = '<span class="val-blue">+3.5</span>';
      } else {
        card.innerHTML = '<span class="val-blue">3.5</span> + (<span class="val-coral">−3.5</span>) = <span class="val-zero">0</span>';
      }
    }

    function setStep(step) {
      currentStep = step;
      document.getElementById('btn1').classList.toggle('active', step === 1);
      document.getElementById('btn2').classList.toggle('active', step === 2);

      const v1 = document.getElementById('vec1');
      const v2 = document.getElementById('vec2');
      const gTurn = document.getElementById('guide-turn');
      const gZero = document.getElementById('guide-zero');

      if (step === 1) {
        v1.style.opacity = '1';
        v2.style.opacity = '0';
        gTurn.style.opacity = '0.75';
        gZero.style.opacity = '0';
      } else {
        v1.style.opacity = '1';
        v2.style.opacity = '1';
        gTurn.style.opacity = '0.75';
        gZero.style.opacity = '0.75';
      }

      renderMath(step);
    }

    function togglePlay() {
      const btn = document.getElementById('btnPlay');
      if (autoPlayTimer) {
        clearInterval(autoPlayTimer);
        autoPlayTimer = null;
        btn.textContent = '▶ Auto';
        btn.classList.remove('active');
      } else {
        btn.textContent = '⏸ Pause';
        btn.classList.add('active');
        autoPlayTimer = setInterval(() => {
          setStep(currentStep === 1 ? 2 : 1);
        }, 2800);
      }
    }

    // Initialize
    setStep(1);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Vector Representation on a Number Line</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      width: 100%;
      min-height: 100%;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 8px;
    }
    .main-box {
      width: 100%;
      max-width: 640px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 12px;
    }
    .badge-row {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      justify-content: center;
      width: 100%;
    }
    .badge {
      font-size: 13.5px;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 20px;
      border: 1.5px solid #cbd5e1;
      background: #f8fafc;
      color: #334155;
      cursor: pointer;
      transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
      user-select: none;
      -webkit-tap-highlight-color: transparent;
    }
    .badge:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }
    .badge.active-pos {
      background: #eff6ff;
      border-color: #2563eb;
      color: #1d4ed8;
      font-weight: 700;
    }
    .badge.active-neg {
      background: #fff1f2;
      border-color: #e11d48;
      color: #be123c;
      font-weight: 700;
    }
    .badge.active-all {
      background: #1e2945;
      border-color: #1e2945;
      color: #ffffff;
      font-weight: 700;
    }
    .badge.active-all:hover {
      background: #0f172a;
      border-color: #0f172a;
    }
    .svg-wrap {
      width: 100%;
      background: transparent;
      border: none;
      box-shadow: none;
      padding: 0;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }
    .vector-group {
      transition: opacity 0.25s ease;
    }
    .dimmed {
      opacity: 0.12;
    }
    .tick-label {
      font-size: 14px;
      fill: #334155;
      font-weight: 500;
      text-anchor: middle;
      font-family: inherit;
    }
    .tick-label.zero {
      font-weight: 800;
      font-size: 15px;
      fill: #0f172a;
    }
    .vector-tag {
      font-size: 13.5px;
      font-weight: 700;
      font-family: inherit;
    }
    .sub-tag {
      font-size: 12.5px;
      font-weight: 600;
      font-family: inherit;
    }
  </style>
</head>
<body>

<div class="main-box">
  <div class="badge-row" role="group" aria-label="Vector display selection">
    <button class="badge active-all" id="btn-all" onclick="showMode('all')">Show Both</button>
    <button class="badge" id="btn-pos" onclick="showMode('pos')">+3.5 (Right)</button>
    <button class="badge" id="btn-neg" onclick="showMode('neg')">−3.5 (Left)</button>
  </div>

  <div class="svg-wrap">
    <svg viewBox="0 0 600 205" aria-label="Number line showing rational number vectors from -6 to +6 centered at 0">
      <defs>
        
        <marker id="arrow-blue" markerWidth="9" markerHeight="9" refX="7" refY="4.5" orient="auto">
          <polygon points="0 1, 8 4.5, 0 8" fill="#2563eb" />
        </marker>
        
        <marker id="arrow-coral" markerWidth="9" markerHeight="9" refX="1" refY="4.5" orient="auto">
          <polygon points="8 1, 0 4.5, 8 8" fill="#e11d48" />
        </marker>
      </defs>

      
      <g stroke="#f1f5f9" stroke-width="1.2">
        <line x1="50" y1="10" x2="50" y2="185" />
        <line x1="91.66" y1="10" x2="91.66" y2="185" />
        <line x1="133.33" y1="10" x2="133.33" y2="185" />
        <line x1="175" y1="10" x2="175" y2="185" />
        <line x1="216.66" y1="10" x2="216.66" y2="185" />
        <line x1="258.33" y1="10" x2="258.33" y2="185" />
        <line x1="300" y1="10" x2="300" y2="185" stroke="#e2e8f0" stroke-dasharray="3,3" />
        <line x1="341.66" y1="10" x2="341.66" y2="185" />
        <line x1="383.33" y1="10" x2="383.33" y2="185" />
        <line x1="425" y1="10" x2="425" y2="185" />
        <line x1="466.66" y1="10" x2="466.66" y2="185" />
        <line x1="508.33" y1="10" x2="508.33" y2="185" />
        <line x1="550" y1="10" x2="550" y2="185" />
      </g>

      
      
      <g id="vec-neg" class="vector-group">
        
        <rect x="64" y="10" width="180" height="48" rx="8" fill="#fff1f2" stroke="#fecdd3" stroke-width="1.5" />
        <text x="154" y="29" fill="#e11d48" class="vector-tag" text-anchor="middle">Direction: Left (−)</text>
        <text x="154" y="47" fill="#9f1239" class="sub-tag" text-anchor="middle">Magnitude: 3.5</text>

        
        <line x1="154.17" y1="68" x2="154.17" y2="135" stroke="#fda4af" stroke-width="1.5" stroke-dasharray="3,3" />

        
        <line x1="300" y1="68" x2="160" y2="68" stroke="#e11d48" stroke-width="3" marker-end="url(#arrow-coral)" />
        <circle cx="300" cy="68" r="3.5" fill="#e11d48" />
        <circle cx="154.17" cy="135" r="4" fill="#e11d48" />
      </g>

      
      
      <g id="vec-pos" class="vector-group">
        
        <rect x="356" y="10" width="180" height="48" rx="8" fill="#eff6ff" stroke="#bfdbfe" stroke-width="1.5" />
        <text x="446" y="29" fill="#2563eb" class="vector-tag" text-anchor="middle">Direction: Right (+)</text>
        <text x="446" y="47" fill="#1e40af" class="sub-tag" text-anchor="middle">Magnitude: 3.5</text>

        
        <line x1="445.83" y1="68" x2="445.83" y2="135" stroke="#93c5fd" stroke-width="1.5" stroke-dasharray="3,3" />

        
        <line x1="300" y1="68" x2="440" y2="68" stroke="#2563eb" stroke-width="3" marker-end="url(#arrow-blue)" />
        <circle cx="300" cy="68" r="3.5" fill="#2563eb" />
        <circle cx="445.83" cy="135" r="4" fill="#2563eb" />
      </g>

      
      <line x1="28" y1="135" x2="572" y2="135" stroke="#1e2945" stroke-width="2.5" />
      
      <polygon points="26,135 36,129 36,141" fill="#1e2945" />
      <polygon points="574,135 564,129 564,141" fill="#1e2945" />

      
      
      <line x1="50.00" y1="126" x2="50.00" y2="144" stroke="#1e2945" stroke-width="1.8" />
      <text x="50.00" y="162" class="tick-label">−6</text>

      
      <line x1="91.66" y1="128" x2="91.66" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="91.66" y="162" class="tick-label">−5</text>

      
      <line x1="133.33" y1="128" x2="133.33" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="133.33" y="162" class="tick-label">−4</text>

      
      <line x1="154.17" y1="130" x2="154.17" y2="140" stroke="#e11d48" stroke-width="2.2" />
      <text x="154.17" y="180" fill="#e11d48" font-size="12.5" font-weight="700" text-anchor="middle">−3.5</text>

      
      <line x1="175.00" y1="128" x2="175.00" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="175.00" y="162" class="tick-label">−3</text>

      
      <line x1="216.66" y1="128" x2="216.66" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="216.66" y="162" class="tick-label">−2</text>

      
      <line x1="258.33" y1="128" x2="258.33" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="258.33" y="162" class="tick-label">−1</text>

      
      <line x1="300.00" y1="122" x2="300.00" y2="148" stroke="#0f172a" stroke-width="2.8" />
      <text x="300.00" y="164" class="tick-label zero">0</text>
      <circle cx="300" cy="135" r="4.5" fill="#0f172a" />

      
      <line x1="341.66" y1="128" x2="341.66" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="341.66" y="162" class="tick-label">1</text>

      
      <line x1="383.33" y1="128" x2="383.33" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="383.33" y="162" class="tick-label">2</text>

      
      <line x1="425.00" y1="128" x2="425.00" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="425.00" y="162" class="tick-label">3</text>

      
      <line x1="445.83" y1="130" x2="445.83" y2="140" stroke="#2563eb" stroke-width="2.2" />
      <text x="445.83" y="180" fill="#2563eb" font-size="12.5" font-weight="700" text-anchor="middle">+3.5</text>

      
      <line x1="466.66" y1="128" x2="466.66" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="466.66" y="162" class="tick-label">4</text>

      
      <line x1="508.33" y1="128" x2="508.33" y2="142" stroke="#64748b" stroke-width="1.5" />
      <text x="508.33" y="162" class="tick-label">5</text>

      
      <line x1="550.00" y1="126" x2="550.00" y2="144" stroke="#1e2945" stroke-width="1.8" />
      <text x="550.00" y="162" class="tick-label">6</text>
    </svg>
  </div>
</div>

<script>
  function showMode(mode) {
    const posGroup = document.getElementById('vec-pos');
    const negGroup = document.getElementById('vec-neg');
    const btnAll = document.getElementById('btn-all');
    const btnPos = document.getElementById('btn-pos');
    const btnNeg = document.getElementById('btn-neg');

    btnAll.className = 'badge';
    btnPos.className = 'badge';
    btnNeg.className = 'badge';

    if (mode === 'all') {
      posGroup.classList.remove('dimmed');
      negGroup.classList.remove('dimmed');
      btnAll.classList.add('active-all');
    } else if (mode === 'pos') {
      posGroup.classList.remove('dimmed');
      negGroup.classList.add('dimmed');
      btnPos.classList.add('active-pos');
    } else if (mode === 'neg') {
      negGroup.classList.remove('dimmed');
      posGroup.classList.add('dimmed');
      btnNeg.classList.add('active-neg');
    }
  }
</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;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 16px 12px;
      min-height: 100%;
      user-select: none;
    }

    /* Controls Header */
    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 8px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .btn-step {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #475569;
      padding: 6px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .btn-step.active {
      background: #e0f2fe;
      border-color: #0284c7;
      color: #0369a1;
      box-shadow: 0 0 0 1px #0284c7;
    }
    .play-btn {
      background: #0284c7;
      color: #ffffff;
      border: none;
      border-radius: 50%;
      width: 32px;
      height: 32px;
      font-size: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: background 0.2s ease;
    }
    .play-btn:hover {
      background: #0369a1;
    }

    /* Diagram Stage */
    .stage {
      width: 100%;
      max-width: 620px;
      position: relative;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    /* SVG Elements */
    .axis-line {
      stroke: #64748b;
      stroke-width: 2.5;
      stroke-linecap: round;
    }
    .tick {
      stroke: #64748b;
      stroke-width: 2;
    }
    .subtick {
      stroke: #cbd5e1;
      stroke-width: 1.5;
    }
    .tick-label {
      font-size: 13px;
      font-weight: 600;
      fill: #475569;
      text-anchor: middle;
      font-family: inherit;
    }

    /* Vectors */
    .vec-1, .vec-2, .result-indicator {
      transition: opacity 0.4s ease, transform 0.4s ease;
    }
    .vector-coral {
      stroke: #f43f5e;
      stroke-width: 3.5;
      fill: none;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    .vector-coral-arr {
      fill: #f43f5e;
    }
    .vec-label {
      font-size: 14px;
      font-weight: 700;
      fill: #e11d48;
      text-anchor: middle;
      font-family: inherit;
    }

    /* Drop / Result line */
    .drop-line {
      stroke: #0284c7;
      stroke-width: 2;
      stroke-dasharray: 4 3;
    }
    .result-badge {
      fill: #0284c7;
    }
    .result-text {
      fill: #ffffff;
      font-size: 13px;
      font-weight: 700;
      text-anchor: middle;
      dominant-baseline: middle;
      font-family: inherit;
    }
    .result-glow {
      fill: #38bdf8;
      opacity: 0.35;
      animation: pulse 2s infinite ease-in-out;
    }

    @keyframes pulse {
      0%, 100% { transform: scale(1); opacity: 0.35; }
      50% { transform: scale(1.4); opacity: 0.65; }
    }

    /* Equation Card */
    .card-eq {
      margin-top: 6px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 16px;
      width: 100%;
      max-width: 540px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
      text-align: center;
    }
    .main-math {
      font-size: 18px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: 0.5px;
    }
    .coral-txt {
      color: #e11d48;
    }
    .blue-txt {
      color: #0284c7;
    }
    .sub-math {
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      display: flex;
      align-items: center;
      gap: 6px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .sub-tag {
      background: #e2e8f0;
      padding: 2px 6px;
      border-radius: 4px;
      color: #334155;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button id="playBtn" class="play-btn" aria-label="Play/Pause">⏸</button>
    <button class="btn-step active" onclick="setStep(0)">1: Dive -2.5</button>
    <button class="btn-step" onclick="setStep(1)">2: Dive -1.75</button>
    <button class="btn-step" onclick="setStep(2)">3: Total -4.25</button>
  </div>

  
  <div class="stage">
    <svg viewBox="0 0 600 200">
      <defs>
        
        <marker id="arrow-coral" viewBox="0 0 10 10" refX="2" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 10 1 L 0 5 L 10 9 z" fill="#f43f5e"/>
        </marker>
        <filter id="glow" x="-20%" y="-20%" width="140%" height="140%">
          <feGaussianBlur stdDeviation="3" result="blur" />
          <feComposite in="SourceGraphic" in2="blur" operator="over" />
        </filter>
      </defs>

      
      
      <line x1="100" y1="145" x2="100" y2="155" class="subtick" />
      <line x1="180" y1="145" x2="180" y2="155" class="subtick" />
      <line x1="260" y1="145" x2="260" y2="155" class="subtick" />
      <line x1="340" y1="145" x2="340" y2="155" class="subtick" />
      <line x1="420" y1="145" x2="420" y2="155" class="subtick" />
      <line x1="500" y1="145" x2="500" y2="155" class="subtick" />

      
      <line x1="30" y1="150" x2="570" y2="150" class="axis-line" />
      
      <path d="M 36 144 L 26 150 L 36 156" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
      
      <path d="M 564 144 L 574 150 L 564 156" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />

      
      
      <line x1="60" y1="142" x2="60" y2="158" class="tick" />
      <text x="60" y="174" class="tick-label">-6</text>

      
      <line x1="140" y1="142" x2="140" y2="158" class="tick" />
      <text x="140" y="174" class="tick-label">-5</text>

      
      <line x1="220" y1="142" x2="220" y2="158" class="tick" />
      <text x="220" y="174" class="tick-label">-4</text>

      
      <line x1="300" y1="142" x2="300" y2="158" class="tick" />
      <text x="300" y="174" class="tick-label">-3</text>

      
      <line x1="380" y1="142" x2="380" y2="158" class="tick" />
      <text x="380" y="174" class="tick-label">-2</text>

      
      <line x1="460" y1="142" x2="460" y2="158" class="tick" />
      <text x="460" y="174" class="tick-label">-1</text>

      
      <line x1="540" y1="142" x2="540" y2="158" class="tick" />
      <text x="540" y="174" class="tick-label">0</text>

      
      <circle cx="540" cy="150" r="4" fill="#64748b" />

      
      <g id="vec1" class="vec-1" opacity="1">
        
        <path d="M 536 142 C 500 95, 380 95, 344 142" class="vector-coral" marker-end="url(#arrow-coral)" />
        <rect x="415" y="80" width="50" height="22" rx="4" fill="#fff" stroke="#fecdd3" stroke-width="1.5" />
        <text x="440" y="96" class="vec-label">-2.5</text>
      </g>

      
      <g id="vec2" class="vec-2" opacity="0">
        
        <path d="M 336 142 C 310 95, 230 95, 204 142" class="vector-coral" marker-end="url(#arrow-coral)" />
        <rect x="245" y="80" width="50" height="22" rx="4" fill="#fff" stroke="#fecdd3" stroke-width="1.5" />
        <text x="270" y="96" class="vec-label">-1.75</text>
      </g>

      
      <g id="vec3" class="result-indicator" opacity="0">
        
        <line x1="200" y1="50" x2="200" y2="148" class="drop-line" />
        
        <circle cx="200" cy="150" r="10" class="result-glow" />
        <circle cx="200" cy="150" r="5" fill="#0284c7" />

        
        <g transform="translate(200, 34)">
          <rect x="-56" y="-14" width="112" height="28" rx="14" class="result-badge" filter="url(#glow)" />
          <text x="0" y="1" class="result-text">Result: -4.25</text>
        </g>
      </g>
    </svg>
  </div>

  
  <div class="card-eq">
    <div class="main-math" id="eqMain">
      <span class="coral-txt">(-2.5)</span> + <span class="coral-txt">(-1.75)</span> = <span class="blue-txt">-4.25</span>
    </div>
    <div class="sub-math" id="eqSub">
      <span class="sub-tag">Same Sign: Add Absolute Values</span>
      <span>|-2.5| + |-1.75| = 4.25 → Total is <strong>-4.25</strong></span>
    </div>
  </div>

  <script>
    let currentStep = 0;
    let isPlaying = true;
    let timer = null;

    const v1 = document.getElementById('vec1');
    const v2 = document.getElementById('vec2');
    const v3 = document.getElementById('vec3');
    const playBtn = document.getElementById('playBtn');
    const buttons = document.querySelectorAll('.btn-step');

    function updateStep() {
      // Step button active state
      buttons.forEach((btn, idx) => {
        btn.classList.toggle('active', idx === currentStep);
      });

      // SVG Elements visibility
      if (currentStep === 0) {
        v1.style.opacity = '1';
        v2.style.opacity = '0';
        v3.style.opacity = '0';
      } else if (currentStep === 1) {
        v1.style.opacity = '1';
        v2.style.opacity = '1';
        v3.style.opacity = '0';
      } else {
        v1.style.opacity = '1';
        v2.style.opacity = '1';
        v3.style.opacity = '1';
      }
    }

    function setStep(idx) {
      currentStep = idx;
      updateStep();
    }

    function nextStep() {
      currentStep = (currentStep + 1) % 3;
      updateStep();
    }

    function startAutoPlay() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 3200);
      isPlaying = true;
      playBtn.textContent = '⏸';
    }

    function stopAutoPlay() {
      if (timer) clearInterval(timer);
      timer = null;
      isPlaying = false;
      playBtn.textContent = '▶';
    }

    playBtn.addEventListener('click', () => {
      if (isPlaying) {
        stopAutoPlay();
      } else {
        nextStep();
        startAutoPlay();
      }
    });

    // Initialize
    updateStep();
    startAutoPlay();
  </script>
</body>
</html>

OGM.8.NO.3

Aligned learning resources

Related diagrams