<!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">
  <title>Acid and Metal Carbonate Reaction</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: #f8fafc;
      color: #1e293b;
      padding: 16px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    .nav-tabs {
      display: flex;
      gap: 6px;
      width: 100%;
      max-width: 480px;
      background: #e2e8f0;
      padding: 4px;
      border-radius: 12px;
      margin-bottom: 12px;
    }

    .tab-btn {
      flex: 1;
      border: none;
      background: transparent;
      padding: 8px 4px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.25s ease;
      text-align: center;
    }

    .tab-btn.active {
      background: #ffffff;
      color: #0f172a;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.06);
    }

    .stage {
      width: 100%;
      max-width: 500px;
      display: flex;
      flex-direction: column;
      gap: 16px;
      position: relative;
    }

    .section-title {
      font-size: 12px;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      font-weight: 700;
      color: #94a3b8;
      margin-bottom: 6px;
    }

    /* Reactants / Products Panels */
    .tiles-row {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
      gap: 10px;
      width: 100%;
    }

    .tile {
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px;
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
      transition: all 0.3s ease;
      position: relative;
    }

    .tile-name {
      font-size: 13px;
      font-weight: 600;
      color: #475569;
    }

    .atom-group {
      display: flex;
      gap: 4px;
      align-items: center;
      justify-content: center;
    }

    .pill {
      font-size: 13px;
      font-weight: 700;
      padding: 4px 8px;
      border-radius: 8px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
      border: 1.5px solid transparent;
    }

    /* Atom Color Codings */
    .pill-h { background: #dbeafe; color: #1d4ed8; border-color: #93c5fd; }
    .pill-acid { background: #ccfbf1; color: #0f766e; border-color: #5eead4; }
    .pill-metal { background: #fef3c7; color: #b45309; border-color: #fcd34d; }
    .pill-c { background: #f1f5f9; color: #334155; border-color: #cbd5e1; }
    .pill-o { background: #fee2e2; color: #b91c1c; border-color: #fca5a5; }

    /* Focus States */
    .tile.dimmed, .pill.dimmed {
      opacity: 0.3;
      transform: scale(0.96);
    }

    .tile.highlight-salt {
      border-color: #0d9488;
      box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
    }

    .tile.highlight-water {
      border-color: #2563eb;
      box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
    }

    .tile.highlight-gas {
      border-color: #f59e0b;
      box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.15);
    }

    /* Flow Arrow */
    .flow-indicator {
      display: flex;
      align-items: center;
      justify-content: center;
      color: #94a3b8;
      font-size: 18px;
      font-weight: bold;
    }

    /* Product sub-tags */
    .origin-badge {
      font-size: 11px;
      font-weight: 600;
      padding: 2px 8px;
      border-radius: 6px;
      background: #f1f5f9;
      color: #64748b;
    }

    .gas-bubble {
      display: inline-block;
      animation: float 2s infinite ease-in-out;
    }

    @keyframes float {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-3px); }
    }
  </style>
</head>
<body>

  
  <div class="nav-tabs">
    <button class="tab-btn active" onclick="setStep(0)">All</button>
    <button class="tab-btn" onclick="setStep(1)">Salt</button>
    <button class="tab-btn" onclick="setStep(2)">Water</button>
    <button class="tab-btn" onclick="setStep(3)">Gas 🫧</button>
  </div>

  <div class="stage">
    
    <div>
      <div class="section-title">Reactants</div>
      <div class="tiles-row">
        
        <div class="tile" id="tile-acid">
          <span class="tile-name">Acid</span>
          <div class="atom-group">
            <span class="pill pill-h" id="atom-h">H⁺</span>
            <span class="pill pill-acid" id="atom-cl">Cl⁻</span>
          </div>
        </div>
        
        <div class="tile" id="tile-carb">
          <span class="tile-name">Carbonate</span>
          <div class="atom-group">
            <span class="pill pill-metal" id="atom-mg">Mg²⁺</span>
            <span class="pill pill-c" id="atom-co2">CO₂</span>
            <span class="pill pill-o" id="atom-o">O²⁻</span>
          </div>
        </div>
      </div>
    </div>

    <div class="flow-indicator">↓</div>

    
    <div>
      <div class="section-title">Products</div>
      <div class="tiles-row">
        
        <div class="tile" id="prod-salt">
          <span class="tile-name">Salt</span>
          <div class="atom-group">
            <span class="pill pill-metal" id="p-mg">Mg²⁺</span>
            <span class="pill pill-acid" id="p-cl">Cl⁻</span>
          </div>
          <span class="origin-badge">Metal + Acid</span>
        </div>

        
        <div class="tile" id="prod-water">
          <span class="tile-name">Water</span>
          <div class="atom-group">
            <span class="pill pill-h" id="p-h">H⁺</span>
            <span class="pill pill-o" id="p-o">O²⁻</span>
          </div>
          <span class="origin-badge">H + Oxygen</span>
        </div>

        
        <div class="tile" id="prod-gas">
          <span class="tile-name">CO₂ Gas <span class="gas-bubble">🫧</span></span>
          <div class="atom-group">
            <span class="pill pill-c" id="p-co2">CO₂</span>
          </div>
          <span class="origin-badge">Escapes</span>
        </div>
      </div>
    </div>
  </div>

  <script>
    const tabs = document.querySelectorAll('.tab-btn');
    const allPills = document.querySelectorAll('.pill');
    const allTiles = document.querySelectorAll('.tile');

    function resetVisuals() {
      allPills.forEach(p => p.classList.remove('dimmed'));
      allTiles.forEach(t => {
        t.classList.remove('dimmed', 'highlight-salt', 'highlight-water', 'highlight-gas');
      });
    }

    function setStep(index) {
      tabs.forEach((t, i) => t.classList.toggle('active', i === index));
      resetVisuals();

      if (index === 1) { // Salt Focus
        document.getElementById('prod-salt').classList.add('highlight-salt');
        
        // Dim non-salt components
        document.getElementById('atom-h').classList.add('dimmed');
        document.getElementById('atom-co2').classList.add('dimmed');
        document.getElementById('atom-o').classList.add('dimmed');
        document.getElementById('prod-water').classList.add('dimmed');
        document.getElementById('prod-gas').classList.add('dimmed');
      } 
      else if (index === 2) { // Water Focus
        document.getElementById('prod-water').classList.add('highlight-water');
        
        // Dim non-water components
        document.getElementById('atom-cl').classList.add('dimmed');
        document.getElementById('atom-mg').classList.add('dimmed');
        document.getElementById('atom-co2').classList.add('dimmed');
        document.getElementById('prod-salt').classList.add('dimmed');
        document.getElementById('prod-gas').classList.add('dimmed');
      } 
      else if (index === 3) { // CO2 Focus
        document.getElementById('prod-gas').classList.add('highlight-gas');
        
        // Dim non-gas components
        document.getElementById('atom-h').classList.add('dimmed');
        document.getElementById('atom-cl').classList.add('dimmed');
        document.getElementById('atom-mg').classList.add('dimmed');
        document.getElementById('atom-o').classList.add('dimmed');
        document.getElementById('prod-salt').classList.add('dimmed');
        document.getElementById('prod-water').classList.add('dimmed');
      }
    }
  </script>
</body>
</html>

Reactions of Acids with Metals and Carbonates

<!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="1:1">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      background: #ffffff;
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      width: 100%;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
      gap: 10px;
      width: 100%;
    }
    .rxn-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .badge {
      font-size: 11px;
      font-weight: 700;
      padding: 3px 8px;
      border-radius: 6px;
      text-align: center;
      letter-spacing: 0.2px;
    }
    .badge-2 { background: #e0f2fe; color: #0284c7; }
    .badge-3 { background: #fef3c7; color: #d97706; }

    .title {
      font-size: 13px;
      font-weight: 700;
      text-align: center;
      color: #1e2945;
    }
    .products-list {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .item {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 6px 8px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: 12px;
      font-weight: 600;
    }
    .tag {
      font-size: 10px;
      padding: 2px 6px;
      border-radius: 4px;
      font-weight: 700;
    }
    .tag-salt { background: #f1f5f9; color: #475569; }
    .tag-water { background: #e0f2fe; color: #0369a1; }
    .tag-gas { background: #ecfdf5; color: #059669; }

    .test-box {
      margin-top: 2px;
      background: #ffffff;
      border: 1px dashed #cbd5e1;
      border-radius: 8px;
      padding: 8px 6px;
      text-align: center;
      cursor: pointer;
      user-select: none;
      transition: background 0.2s, border-color 0.2s;
    }
    .test-box:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }
    .test-label {
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      margin-bottom: 2px;
    }
    .test-result {
      font-size: 12px;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      color: #1e2945;
    }
    .hint {
      font-size: 11px;
      color: #64748b;
      text-align: center;
      font-weight: 500;
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="rxn-card">
      <div class="badge badge-2">2 Products (No O in reactants)</div>
      <div class="title">Acid + Metal</div>
      
      <div class="products-list">
        <div class="item">
          <span>🧂 Salt</span>
          <span class="tag tag-salt">(aq)</span>
        </div>
        <div class="item">
          <span>🫧 Hydrogen (H₂)</span>
          <span class="tag tag-gas">(g)</span>
        </div>
      </div>

      <div class="test-box" onclick="testGas('pop')">
        <div class="test-label">Gas Test</div>
        <div class="test-result" id="pop-result">🔥 Lighted splint → 💥 Pop!</div>
      </div>
    </div>

    
    <div class="rxn-card">
      <div class="badge badge-3">3 Products (CO₃ provides C & O)</div>
      <div class="title">Acid + Metal Carbonate</div>
      
      <div class="products-list">
        <div class="item">
          <span>🧂 Salt</span>
          <span class="tag tag-salt">(aq)</span>
        </div>
        <div class="item">
          <span>💧 Water (H₂O)</span>
          <span class="tag tag-water">(l)</span>
        </div>
        <div class="item">
          <span>🫧 Carbon Dioxide (CO₂)</span>
          <span class="tag tag-gas">(g)</span>
        </div>
      </div>

      <div class="test-box" onclick="testGas('lime')">
        <div class="test-label">Gas Test</div>
        <div class="test-result" id="lime-result">🧪 Limewater → 🥛 Cloudy</div>
      </div>
    </div>
  </div>

  <div class="hint">Tap a gas test box to test the product gas</div>

  <script>
    function testGas(type) {
      if (type === 'pop') {
        const el = document.getElementById('pop-result');
        el.innerHTML = '💥 SQUEAKY POP!';
        el.style.color = '#dc2626';
        setTimeout(() => {
          el.innerHTML = '🔥 Lighted splint → 💥 Pop!';
          el.style.color = '#1e2945';
        }, 1200);
      } else if (type === 'lime') {
        const el = document.getElementById('lime-result');
        el.innerHTML = '🥛 CLOUDY WHITE!';
        el.style.color = '#0284c7';
        setTimeout(() => {
          el.innerHTML = '🧪 Limewater → 🥛 Cloudy';
          el.style.color = '#1e2945';
        }, 1200);
      }
    }
  </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="1:1">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      background: #ffffff;
      color: #1e2945;
      padding: 16px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      user-select: none;
    }

    /* General Equation Card */
    .general-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 12px;
      text-align: center;
    }

    .equation-row {
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px;
      font-size: 14px;
      font-weight: 700;
    }

    .pill {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 4px 10px;
      border-radius: 6px;
      font-size: 13px;
      line-height: 1.2;
    }

    .pill-acid { background: #eff6ff; color: #2563eb; border: 1px solid #bfdbfe; }
    .pill-metal { background: #fef3c7; color: #b45309; border: 1px solid #fde68a; }
    .pill-salt { background: #f0fdf4; color: #15803d; border: 1px solid #bbf7d0; }
    .pill-gas { background: #f1f5f9; color: #475569; border: 1px solid #cbd5e1; }
    .op { color: #94a3b8; font-weight: 800; font-size: 15px; }

    /* Selectors */
    .section-title {
      font-size: 11px;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      color: #64748b;
      font-weight: 700;
      margin-bottom: 6px;
    }

    .btn-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 6px;
    }

    .choice-btn {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 4px;
      cursor: pointer;
      font-size: 13px;
      font-weight: 600;
      color: #1e2945;
      text-align: center;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 2px;
      transition: all 0.2s ease;
    }

    .choice-btn .sub {
      font-size: 11px;
      font-weight: 500;
      color: #2563eb;
    }

    .choice-btn.active-acid {
      border-color: #2563eb;
      background: #eff6ff;
      box-shadow: 0 0 0 1px #2563eb;
    }

    .choice-btn.active-metal {
      border-color: #f59e0b;
      background: #fffbeb;
      box-shadow: 0 0 0 1px #f59e0b;
    }

    /* Live Output Box */
    .output-box {
      background: #ffffff;
      border: 2px dashed #cbd5e1;
      border-radius: 12px;
      padding: 14px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 10px;
      min-height: 105px;
    }

    .live-equation {
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px;
      font-size: 14px;
      font-weight: 700;
      text-align: center;
    }

    .salt-builder {
      display: inline-flex;
      border-radius: 6px;
      overflow: hidden;
      border: 1px solid #cbd5e1;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    }

    .salt-metal-part {
      background: #fef3c7;
      color: #b45309;
      padding: 4px 6px;
      border-right: 1px dashed #f59e0b;
    }

    .salt-acid-part {
      background: #eff6ff;
      color: #2563eb;
      padding: 4px 6px;
    }
  </style>
</head>
<body>

  
  <div class="general-card">
    <div class="equation-row">
      <span class="pill pill-acid">Acid</span>
      <span class="op">+</span>
      <span class="pill pill-metal">Metal</span>
      <span class="op">→</span>
      <span class="pill pill-salt">Salt</span>
      <span class="op">+</span>
      <span class="pill pill-gas">Hydrogen</span>
    </div>
  </div>

  
  <div>
    <div class="section-title">1. Choose Acid (Sets Ending)</div>
    <div class="btn-grid" id="acidGroup">
      <button class="choice-btn active-acid" data-acid="Hydrochloric acid" data-salt="Chloride">
        <span>Hydrochloric</span>
        <span class="sub">...chloride</span>
      </button>
      <button class="choice-btn" data-acid="Sulfuric acid" data-salt="Sulfate">
        <span>Sulfuric</span>
        <span class="sub">...sulfate</span>
      </button>
      <button class="choice-btn" data-acid="Nitric acid" data-salt="Nitrate">
        <span>Nitric</span>
        <span class="sub">...nitrate</span>
      </button>
    </div>
  </div>

  
  <div>
    <div class="section-title">2. Choose Metal (Sets Prefix)</div>
    <div class="btn-grid" id="metalGroup">
      <button class="choice-btn active-metal" data-metal="Magnesium">
        <span>Magnesium</span>
      </button>
      <button class="choice-btn" data-metal="Zinc">
        <span>Zinc</span>
      </button>
      <button class="choice-btn" data-metal="Iron">
        <span>Iron</span>
      </button>
    </div>
  </div>

  
  <div class="output-box">
    <div class="live-equation">
      <span class="pill pill-acid" id="outAcid">Hydrochloric acid</span>
      <span class="op">+</span>
      <span class="pill pill-metal" id="outMetal">Magnesium</span>
      <span class="op">→</span>
      <span class="salt-builder">
        <span class="salt-metal-part" id="saltPrefix">Magnesium</span>
        <span class="salt-acid-part" id="saltSuffix">Chloride</span>
      </span>
      <span class="op">+</span>
      <span class="pill pill-gas">Hydrogen ↑</span>
    </div>
  </div>

  <script>
    let selectedAcid = "Hydrochloric acid";
    let selectedSuffix = "Chloride";
    let selectedMetal = "Magnesium";

    const acidButtons = document.querySelectorAll('#acidGroup .choice-btn');
    const metalButtons = document.querySelectorAll('#metalGroup .choice-btn');

    const outAcid = document.getElementById('outAcid');
    const outMetal = document.getElementById('outMetal');
    const saltPrefix = document.getElementById('saltPrefix');
    const saltSuffix = document.getElementById('saltSuffix');

    function updateView() {
      outAcid.textContent = selectedAcid;
      outMetal.textContent = selectedMetal;
      saltPrefix.textContent = selectedMetal;
      saltSuffix.textContent = selectedSuffix;
    }

    acidButtons.forEach(btn => {
      btn.addEventListener('click', () => {
        acidButtons.forEach(b => b.classList.remove('active-acid'));
        btn.classList.add('active-acid');
        selectedAcid = btn.dataset.acid;
        selectedSuffix = btn.dataset.salt;
        updateView();
      });
    });

    metalButtons.forEach(btn => {
      btn.addEventListener('click', () => {
        metalButtons.forEach(b => b.classList.remove('active-metal'));
        btn.classList.add('active-metal');
        selectedMetal = btn.dataset.metal;
        updateView();
      });
    });
  </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>Acid to Salt Naming Mapper</title>
  <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: #0f172a;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      max-width: 720px;
      margin: 0 auto;
    }
    .tabs {
      display: flex;
      gap: 6px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .tab-btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #334155;
      cursor: pointer;
      transition: background 0.2s, color 0.2s, border-color 0.2s;
    }
    .tab-btn:hover {
      background: #e2e8f0;
    }
    .tab-btn.active {
      background: #7c3aed;
      color: #ffffff;
      border-color: #6d28d9;
    }
    .mapper-list {
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .mapper-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 10px 12px;
      display: grid;
      grid-template-columns: 1.15fr auto 1.15fr auto 1.3fr;
      align-items: center;
      gap: 8px;
      transition: box-shadow 0.2s, border-color 0.2s, opacity 0.2s, background 0.2s;
      cursor: pointer;
    }
    .mapper-card:hover {
      border-color: #c084fc;
    }
    .mapper-card.dimmed {
      opacity: 0.3;
    }
    .mapper-card.active {
      border-color: #9333ea;
      box-shadow: 0 0 0 2px rgba(147, 51, 234, 0.2);
      background: #ffffff;
    }
    .col-cell {
      display: flex;
      flex-direction: column;
      gap: 3px;
      border-radius: 6px;
      padding: 6px 8px;
    }
    .acid-cell {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
    }
    .salt-cell {
      background: #faf5ff;
      border: 1px solid #d8b4fe;
    }
    .example-cell {
      background: #f0fdf4;
      border: 1px solid #86efac;
    }
    .cell-title {
      font-size: 12px;
      font-weight: 700;
      color: #0f172a;
      line-height: 1.2;
    }
    .cell-formula {
      font-size: 12px;
      font-weight: 700;
      color: #1e1b4b;
      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
      letter-spacing: 0.2px;
    }
    .arrow-connector {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 1px;
      color: #4b5563;
      font-size: 11px;
      font-weight: 700;
      user-select: none;
      min-width: 32px;
      text-align: center;
    }
    .arrow-symbol {
      color: #7c3aed;
      font-size: 15px;
      line-height: 1;
    }
    .arrow-label {
      font-size: 11px;
      color: #334155;
      font-weight: 700;
      white-space: nowrap;
    }
    .suffix-badge {
      display: inline-block;
      background: #7c3aed;
      color: #ffffff;
      padding: 1px 5px;
      border-radius: 4px;
      font-weight: 700;
      font-size: 11px;
    }
    .example-title {
      font-size: 12px;
      font-weight: 700;
      color: #14532d;
      line-height: 1.2;
    }
    .example-formula {
      font-size: 12px;
      font-weight: 700;
      color: #14532d;
      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    }
    .summary-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      background: #f3e8ff;
      border: 1px solid #d8b4fe;
      border-radius: 8px;
      padding: 8px 12px;
      font-size: 12px;
      color: #4c1d95;
      font-weight: 700;
      flex-wrap: wrap;
      gap: 6px;
    }
    .summary-pattern {
      display: flex;
      gap: 6px;
      align-items: center;
    }

    /* Mobile Responsive Layout (under 520px) */
    @media (max-width: 520px) {
      body {
        padding: 6px;
        gap: 8px;
      }
      .mapper-card {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: 6px;
        padding: 8px;
      }
      .col-cell {
        display: flex;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        padding: 6px 10px;
      }
      .arrow-connector {
        flex-direction: row;
        gap: 6px;
        padding: 2px 0;
      }
      .arrow-symbol {
        transform: rotate(90deg);
        display: inline-block;
      }
      .summary-bar {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 6px;
        padding: 8px 10px;
      }
    }
  </style>
</head>
<body>

  <div class="tabs">
    <button class="tab-btn active" onclick="selectAcid('all')">All Acids</button>
    <button class="tab-btn" onclick="selectAcid('hydrochloric')">Hydrochloric</button>
    <button class="tab-btn" onclick="selectAcid('sulfuric')">Sulfuric</button>
    <button class="tab-btn" onclick="selectAcid('nitric')">Nitric</button>
  </div>

  <div class="mapper-list">
    
    <div class="mapper-card active" id="card-hydrochloric" onclick="selectAcid('hydrochloric')">
      <div class="col-cell acid-cell">
        <span class="cell-title">Hydrochloric acid</span>
        <span class="cell-formula">HCl</span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell salt-cell">
        <span class="cell-title">Chlor<span class="suffix-badge">-ide</span></span>
        <span class="cell-formula">Cl<sup>−</sup></span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-label">+ Mg</span>
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell example-cell">
        <span class="example-title">Magnesium chloride</span>
        <span class="example-formula">MgCl<sub>2</sub></span>
      </div>
    </div>

    
    <div class="mapper-card active" id="card-sulfuric" onclick="selectAcid('sulfuric')">
      <div class="col-cell acid-cell">
        <span class="cell-title">Sulfuric acid</span>
        <span class="cell-formula">H<sub>2</sub>SO<sub>4</sub></span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell salt-cell">
        <span class="cell-title">Sulf<span class="suffix-badge">-ate</span></span>
        <span class="cell-formula">SO<sub>4</sub><sup>2−</sup></span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-label">+ Zn</span>
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell example-cell">
        <span class="example-title">Zinc sulfate</span>
        <span class="example-formula">ZnSO<sub>4</sub></span>
      </div>
    </div>

    
    <div class="mapper-card active" id="card-nitric" onclick="selectAcid('nitric')">
      <div class="col-cell acid-cell">
        <span class="cell-title">Nitric acid</span>
        <span class="cell-formula">HNO<sub>3</sub></span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell salt-cell">
        <span class="cell-title">Nitr<span class="suffix-badge">-ate</span></span>
        <span class="cell-formula">NO<sub>3</sub><sup>−</sup></span>
      </div>
      
      <div class="arrow-connector">
        <span class="arrow-label">+ Cu</span>
        <span class="arrow-symbol">→</span>
      </div>
      
      <div class="col-cell example-cell">
        <span class="example-title">Copper nitrate</span>
        <span class="example-formula">Cu(NO<sub>3</sub>)<sub>2</sub></span>
      </div>
    </div>
  </div>

  <div class="summary-bar">
    <span>General Rule: Metal + Acid → Salt + Hydrogen</span>
    <div class="summary-pattern">
      <span>Suffixes:</span>
      <span class="suffix-badge">-ide</span>
      <span class="suffix-badge">-ate</span>
    </div>
  </div>

  <script>
    function selectAcid(type) {
      const cards = {
        hydrochloric: document.getElementById('card-hydrochloric'),
        sulfuric: document.getElementById('card-sulfuric'),
        nitric: document.getElementById('card-nitric')
      };

      const buttons = document.querySelectorAll('.tab-btn');
      buttons.forEach(btn => {
        const text = btn.textContent.toLowerCase();
        if ((type === 'all' && text.includes('all')) || (type !== 'all' && text.includes(type))) {
          btn.classList.add('active');
        } else {
          btn.classList.remove('active');
        }
      });

      Object.keys(cards).forEach(key => {
        if (type === 'all') {
          cards[key].classList.add('active');
          cards[key].classList.remove('dimmed');
        } else if (key === type) {
          cards[key].classList.add('active');
          cards[key].classList.remove('dimmed');
        } else {
          cards[key].classList.remove('active');
          cards[key].classList.add('dimmed');
        }
      });
    }
  </script>
</body>
</html>

Metal plus Acid Reaction: Forming Salt and Hydrogen

<!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;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    }

    body {
      background: #ffffff;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 380px;
    }

    /* Top Nav / Stepper Bar */
    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      width: 100%;
      max-width: 480px;
    }

    .step-btn {
      flex: 1;
      padding: 8px 10px;
      font-size: 13px;
      font-weight: 600;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      background: #f8fafc;
      color: #64748b;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      transition: background 0.2s, color 0.2s, box-shadow 0.2s;
    }

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

    .play-btn {
      width: 36px;
      height: 36px;
      padding: 0;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      background: #f8fafc;
      color: #475569;
      font-size: 14px;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-shrink: 0;
    }

    /* Central Display Area */
    .display-box {
      width: 100%;
      max-width: 540px;
      min-height: 110px;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      padding: 16px 12px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      position: relative;
    }

    .step-view {
      position: absolute;
      inset: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease;
    }

    .step-view.active {
      opacity: 1;
      pointer-events: auto;
    }

    /* Equation Typography */
    .eq-row {
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px 8px;
      font-size: 19px;
      font-weight: 700;
      color: #0f172a;
    }

    .eq-part {
      display: inline-flex;
      align-items: baseline;
      white-space: nowrap;
    }

    .state {
      font-size: 12px;
      font-weight: 500;
      color: #64748b;
      margin-left: 2px;
    }

    .op {
      color: #94a3b8;
      font-weight: 500;
      margin: 0 2px;
    }

    .arrow {
      color: #0284c7;
      font-size: 20px;
      margin: 0 4px;
    }

    .sub {
      font-size: 13px;
      vertical-align: sub;
    }

    .coeff {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: #0284c7;
      color: #ffffff;
      font-weight: 800;
      padding: 0 6px;
      border-radius: 4px;
      margin-right: 2px;
      box-shadow: 0 1px 3px rgba(2,132,199,0.3);
    }

    /* Atom Tally Panel */
    .tally-panel {
      width: 100%;
      max-width: 540px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 12px 14px;
    }

    .tally-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 12px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #64748b;
      margin-bottom: 8px;
      padding-bottom: 6px;
      border-bottom: 1px solid #f1f5f9;
    }

    .tally-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
    }

    .atom-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 6px;
      text-align: center;
    }

    .atom-sym {
      font-size: 13px;
      font-weight: 700;
      color: #334155;
      margin-bottom: 4px;
    }

    .atom-compare {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      font-size: 14px;
      font-weight: 700;
    }

    .tally-num {
      min-width: 18px;
    }

    .match-icon {
      font-size: 11px;
      font-weight: 800;
      width: 18px;
      height: 18px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .match-icon.balanced {
      background: #dcfce7;
      color: #16a34a;
    }

    .match-icon.unbalanced {
      background: #fef3c7;
      color: #d97706;
    }

    .status-badge {
      display: inline-flex;
      align-items: center;
      gap: 4px;
      font-size: 11px;
      padding: 2px 8px;
      border-radius: 12px;
      font-weight: 600;
    }

    .status-badge.balanced {
      background: #dcfce7;
      color: #15803d;
    }

    .status-badge.unbalanced {
      background: #fef3c7;
      color: #b45309;
    }
  </style>
</head>
<body>

  
  <div class="nav-bar">
    <button class="step-btn active" onclick="setStep(0)">
      <span>1</span> Word
    </button>
    <button class="step-btn" onclick="setStep(1)">
      <span>2</span> Formula
    </button>
    <button class="step-btn" onclick="setStep(2)">
      <span>3</span> Balanced
    </button>
    <button class="play-btn" id="playBtn" onclick="togglePlay()" aria-label="Toggle Auto-play">
      <span id="playIcon">⏸</span>
    </button>
  </div>

  
  <div class="display-box">
    
    <div class="step-view active" id="view-0">
      <div class="eq-row">
        <span>Magnesium</span>
        <span class="op">+</span>
        <span>Hydrochloric acid</span>
        <span class="arrow">→</span>
        <span>Magnesium chloride</span>
        <span class="op">+</span>
        <span>Hydrogen</span>
      </div>
    </div>

    
    <div class="step-view" id="view-1">
      <div class="eq-row">
        <span class="eq-part">Mg<span class="state">(s)</span></span>
        <span class="op">+</span>
        <span class="eq-part">HCl<span class="state">(aq)</span></span>
        <span class="arrow">→</span>
        <span class="eq-part">MgCl<span class="sub">2</span><span class="state">(aq)</span></span>
        <span class="op">+</span>
        <span class="eq-part">H<span class="sub">2</span><span class="state">(g)</span></span>
      </div>
    </div>

    
    <div class="step-view" id="view-2">
      <div class="eq-row">
        <span class="eq-part">Mg<span class="state">(s)</span></span>
        <span class="op">+</span>
        <span class="eq-part"><span class="coeff">2</span>HCl<span class="state">(aq)</span></span>
        <span class="arrow">→</span>
        <span class="eq-part">MgCl<span class="sub">2</span><span class="state">(aq)</span></span>
        <span class="op">+</span>
        <span class="eq-part">H<span class="sub">2</span><span class="state">(g)</span></span>
      </div>
    </div>
  </div>

  
  <div class="tally-panel">
    <div class="tally-header">
      <span>Reactants</span>
      <span id="balanceStatus" class="status-badge balanced">✓ Balanced</span>
      <span>Products</span>
    </div>

    <div class="tally-grid">
      
      <div class="atom-card">
        <div class="atom-sym">Magnesium (Mg)</div>
        <div class="atom-compare">
          <span class="tally-num" id="l-mg">1</span>
          <span class="match-icon balanced" id="icon-mg">✓</span>
          <span class="tally-num" id="r-mg">1</span>
        </div>
      </div>

      
      <div class="atom-card">
        <div class="atom-sym">Hydrogen (H)</div>
        <div class="atom-compare">
          <span class="tally-num" id="l-h">1</span>
          <span class="match-icon unbalanced" id="icon-h">✕</span>
          <span class="tally-num" id="r-h">2</span>
        </div>
      </div>

      
      <div class="atom-card">
        <div class="atom-sym">Chlorine (Cl)</div>
        <div class="atom-compare">
          <span class="tally-num" id="l-cl">1</span>
          <span class="match-icon unbalanced" id="icon-cl">✕</span>
          <span class="tally-num" id="r-cl">2</span>
        </div>
      </div>
    </div>
  </div>

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

    const data = [
      {
        statusText: 'Word Equation',
        statusClass: 'unbalanced',
        lMg: '1', rMg: '1', mgMatch: true,
        lH: '1', rH: '2', hMatch: false,
        lCl: '1', rCl: '2', clMatch: false
      },
      {
        statusText: 'Unbalanced',
        statusClass: 'unbalanced',
        lMg: '1', rMg: '1', mgMatch: true,
        lH: '1', rH: '2', hMatch: false,
        lCl: '1', rCl: '2', clMatch: false
      },
      {
        statusText: '✓ Balanced',
        statusClass: 'balanced',
        lMg: '1', rMg: '1', mgMatch: true,
        lH: '2', rH: '2', hMatch: true,
        lCl: '2', rCl: '2', clMatch: true
      }
    ];

    function setStep(idx) {
      currentStep = idx;

      // Update Tabs
      document.querySelectorAll('.step-btn').forEach((btn, i) => {
        btn.classList.toggle('active', i === idx);
      });

      // Update Views
      document.querySelectorAll('.step-view').forEach((view, i) => {
        view.classList.toggle('active', i === idx);
      });

      // Update Tally
      const d = data[idx];
      const statusEl = document.getElementById('balanceStatus');
      statusEl.textContent = d.statusText;
      statusEl.className = 'status-badge ' + d.statusClass;

      document.getElementById('l-mg').textContent = d.lMg;
      document.getElementById('r-mg').textContent = d.rMg;
      updateIcon('icon-mg', d.mgMatch);

      document.getElementById('l-h').textContent = d.lH;
      document.getElementById('r-h').textContent = d.rH;
      updateIcon('icon-h', d.hMatch);

      document.getElementById('l-cl').textContent = d.lCl;
      document.getElementById('r-cl').textContent = d.rCl;
      updateIcon('icon-cl', d.clMatch);
    }

    function updateIcon(id, isMatch) {
      const el = document.getElementById(id);
      el.textContent = isMatch ? '✓' : '✕';
      el.className = 'match-icon ' + (isMatch ? 'balanced' : 'unbalanced');
    }

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

    function startTimer() {
      stopTimer();
      timer = setInterval(nextStep, 3500);
    }

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

    function togglePlay() {
      isPlaying = !isPlaying;
      document.getElementById('playIcon').textContent = isPlaying ? '⏸' : '▶';
      if (isPlaying) {
        startTimer();
      } else {
        stopTimer();
      }
    }

    // Initialize
    setStep(0);
    startTimer();
  </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>Metal + Acid Reaction</title>
  <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: #0f172a;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: 100vh;
    }

    /* Equation Summary Header */
    .equation-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      width: 100%;
      max-width: 620px;
      font-size: 13px;
      font-weight: 700;
      flex-wrap: wrap;
      margin-bottom: 12px;
      padding: 4px 0;
    }

    .eq-part {
      padding: 4px 8px;
      border-radius: 6px;
      display: inline-flex;
      align-items: center;
      line-height: 1.2;
      border: 1px solid transparent;
    }

    .eq-metal { background: #e2e8f0; color: #0f172a; border-color: #cbd5e1; }
    .eq-acid  { background: #ffe4e6; color: #881337; border-color: #fecdd3; }
    .eq-salt  { background: #dbeafe; color: #1e3a8a; border-color: #bfdbfe; }
    .eq-gas   { background: #dcfce7; color: #14532d; border-color: #bbf7d0; }
    .eq-op    { color: #334155; font-weight: 800; font-size: 15px; }

    /* Interactive Reaction Stage - NO outer container border/box */
    .stage-container {
      width: 100%;
      max-width: 620px;
      position: relative;
      background: transparent;
      display: flex;
      align-items: stretch;
      gap: 8px;
    }

    .vessel-section {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 6px;
      min-width: 0;
    }

    .section-title {
      font-size: 11px;
      font-weight: 800;
      text-transform: uppercase;
      letter-spacing: 0.6px;
      color: #334155;
      text-align: center;
    }

    /* Sub-panels inside vessels */
    .cards-row {
      display: flex;
      gap: 6px;
      width: 100%;
      height: 175px;
    }

    .card-box {
      flex: 1;
      min-width: 0;
      height: 100%;
      border-radius: 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 8px 4px;
      border: 1.5px solid transparent;
      transition: opacity 0.6s ease, filter 0.6s ease;
      position: relative;
    }

    .card-title {
      font-size: 12px;
      font-weight: 800;
      text-align: center;
      line-height: 1.25;
    }

    .card-formula {
      font-size: 11.5px;
      font-weight: 700;
      margin-top: 2px;
      display: block;
    }

    /* Card Themes - High contrast */
    .card-metal {
      background: linear-gradient(145deg, #f8fafc, #e2e8f0);
      border-color: #94a3b8;
      color: #0f172a;
    }
    .card-acid {
      background: #fff1f2;
      border-color: #fda4af;
      color: #881337;
    }
    .card-salt {
      background: #eff6ff;
      border-color: #93c5fd;
      color: #1e3a8a;
    }
    .card-gas {
      background: #f0fdf4;
      border-color: #86efac;
      color: #14532d;
    }

    /* Arrow between reactants and products */
    .divider-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 0 2px;
    }

    .arrow-badge {
      background: #0284c7;
      border-radius: 50%;
      width: 28px;
      height: 28px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 14px;
      color: #ffffff;
      font-weight: 800;
      box-shadow: 0 1px 3px rgba(0,0,0,0.15);
    }

    /* Visual Particle Representations */
    .particle-zone {
      flex: 1;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    /* Metal Solid Lattice */
    .metal-lattice {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 4px;
    }

    .metal-atom {
      width: 16px;
      height: 16px;
      border-radius: 50%;
      background: linear-gradient(135deg, #cbd5e1, #64748b);
      border: 1.5px solid #334155;
    }

    /* Ion Bubbles */
    .ion-pill {
      font-size: 11px;
      font-weight: 800;
      padding: 2px 5px;
      border-radius: 6px;
      margin: 2px;
      display: inline-flex;
      align-items: center;
      line-height: 1;
    }
    .ion-h { background: #ffe4e6; color: #881337; border: 1px solid #f43f5e; }
    .ion-cl { background: #e0f2fe; color: #0369a1; border: 1px solid #38bdf8; }
    .ion-m { background: #e2e8f0; color: #0f172a; border: 1px solid #64748b; }

    /* Rising gas bubbles */
    .bubbles-container {
      position: relative;
      width: 100%;
      height: 70px;
      overflow: hidden;
    }

    .bubble {
      width: 22px;
      height: 22px;
      border-radius: 50%;
      background: #bbf7d0;
      border: 1.5px solid #16a34a;
      color: #14532d;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 10px;
      font-weight: 800;
      position: absolute;
      bottom: 0;
      animation: floatUp 3s infinite ease-in-out;
    }
    .bubble:nth-child(1) { left: 15%; animation-delay: 0s; }
    .bubble:nth-child(2) { left: 55%; animation-delay: 1.0s; }
    .bubble:nth-child(3) { left: 35%; animation-delay: 2.0s; }

    @keyframes floatUp {
      0% { transform: translateY(0) scale(0.9); opacity: 0; }
      20% { opacity: 1; }
      70% { opacity: 1; }
      100% { transform: translateY(-55px) scale(1.05); opacity: 0; }
    }

    /* Displacement Highlight Overlay / Banner */
    .status-banner {
      width: 100%;
      max-width: 620px;
      margin-top: 10px;
      min-height: 32px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .swap-badge {
      background: #0369a1;
      color: #ffffff;
      font-size: 12px;
      font-weight: 700;
      padding: 6px 14px;
      border-radius: 20px;
      text-align: center;
      transition: opacity 0.5s ease;
      opacity: 0;
    }
    .swap-badge.visible {
      opacity: 1;
    }

    /* Control Stepper */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-top: 10px;
      flex-wrap: wrap;
      width: 100%;
      max-width: 620px;
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    .step-btn {
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      color: #1e293b;
      padding: 7px 12px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
    }
    .step-btn:hover {
      background: #f1f5f9;
    }
    .step-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }

    .play-btn {
      background: #ffffff;
      border: 1px solid #94a3b8;
      color: #0f172a;
      width: 34px;
      height: 34px;
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      font-size: 14px;
      font-weight: bold;
    }
    .play-btn:hover {
      background: #f1f5f9;
    }

    /* Responsive adjustments */
    @media (max-width: 480px) {
      .stage-container {
        flex-direction: column;
        gap: 12px;
      }
      .divider-col {
        transform: rotate(90deg);
        height: 24px;
      }
      .arrow-badge {
        width: 24px;
        height: 24px;
        font-size: 12px;
      }
      .cards-row {
        height: 145px;
      }
      .card-title {
        font-size: 11px;
      }
      .card-formula {
        font-size: 10.5px;
      }
      .equation-bar {
        font-size: 12px;
        gap: 4px;
      }
      .eq-part {
        padding: 3px 6px;
      }
      .controls {
        gap: 6px;
      }
      .step-btn {
        font-size: 11px;
        padding: 6px 9px;
      }
    }
  </style>
</head>
<body>

  
  <div class="equation-bar">
    <span class="eq-part eq-metal">Metal (s)</span>
    <span class="eq-op">+</span>
    <span class="eq-part eq-acid">Acid (aq)</span>
    <span class="eq-op">→</span>
    <span class="eq-part eq-salt">Salt (aq)</span>
    <span class="eq-op">+</span>
    <span class="eq-part eq-gas">Hydrogen (g)</span>
  </div>

  
  <div class="stage-container">
    
    <div class="vessel-section" id="reactantsSection">
      <div class="section-title">Reactants</div>
      <div class="cards-row">
        
        <div class="card-box card-metal" id="cMetal">
          <div class="card-title">
            Metal (solid)
            <span class="card-formula">M (s)</span>
          </div>
          <div class="particle-zone">
            <div class="metal-lattice">
              <div class="metal-atom"></div>
              <div class="metal-atom"></div>
              <div class="metal-atom"></div>
              <div class="metal-atom"></div>
              <div class="metal-atom"></div>
              <div class="metal-atom"></div>
            </div>
          </div>
        </div>
        
        <div class="card-box card-acid" id="cAcid">
          <div class="card-title">
            Dilute Acid
            <span class="card-formula">2H⁺ + 2Cl⁻</span>
          </div>
          <div class="particle-zone" style="flex-direction: column;">
            <div><span class="ion-pill ion-h">H⁺</span><span class="ion-pill ion-cl">Cl⁻</span></div>
            <div><span class="ion-pill ion-cl">Cl⁻</span><span class="ion-pill ion-h">H⁺</span></div>
          </div>
        </div>
      </div>
    </div>

    
    <div class="divider-col">
      <div class="arrow-badge">→</div>
    </div>

    
    <div class="vessel-section" id="productsSection">
      <div class="section-title">Products</div>
      <div class="cards-row">
        
        <div class="card-box card-salt" id="cSalt">
          <div class="card-title">
            Metal Salt
            <span class="card-formula">M²⁺ + 2Cl⁻</span>
          </div>
          <div class="particle-zone" style="flex-direction: column;">
            <div><span class="ion-pill ion-m">M²⁺</span><span class="ion-pill ion-cl">Cl⁻</span></div>
            <div><span class="ion-pill ion-cl">Cl⁻</span></div>
          </div>
        </div>
        
        <div class="card-box card-gas" id="cGas">
          <div class="card-title">
            Hydrogen Gas
            <span class="card-formula">H₂ (g) ↑</span>
          </div>
          <div class="particle-zone">
            <div class="bubbles-container">
              <div class="bubble">H₂</div>
              <div class="bubble">H₂</div>
              <div class="bubble">H₂</div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>

  
  <div class="status-banner">
    <div class="swap-badge" id="swapNotice">✦ Single Displacement: Metal replaces H⁺ in solution ✦</div>
  </div>

  
  <div class="controls">
    <button class="step-btn active" id="btn1" onclick="setStep(0)">1. Reactants</button>
    <button class="step-btn" id="btn2" onclick="setStep(1)">2. Displacement</button>
    <button class="step-btn" id="btn3" onclick="setStep(2)">3. Products</button>
    <button class="play-btn" id="playToggle" onclick="togglePlay()" title="Play / Pause">⏸</button>
  </div>

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

    const cMetal = document.getElementById('cMetal');
    const cAcid = document.getElementById('cAcid');
    const cSalt = document.getElementById('cSalt');
    const cGas = document.getElementById('cGas');
    const swapNotice = document.getElementById('swapNotice');

    const buttons = [
      document.getElementById('btn1'),
      document.getElementById('btn2'),
      document.getElementById('btn3')
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    const playBtn = document.getElementById('playToggle');

    function updateView(step) {
      buttons.forEach((b, i) => b.classList.toggle('active', i === step));

      if (step === 0) {
        // Reactants in focus
        cMetal.style.opacity = '1.0';
        cAcid.style.opacity = '1.0';
        cSalt.style.opacity = '0.3';
        cGas.style.opacity = '0.3';
        swapNotice.classList.remove('visible');
      } else if (step === 1) {
        // Displacement active
        cMetal.style.opacity = '0.9';
        cAcid.style.opacity = '0.9';
        cSalt.style.opacity = '0.9';
        cGas.style.opacity = '0.9';
        swapNotice.classList.add('visible');
      } else if (step === 2) {
        // Products formed
        cMetal.style.opacity = '0.3';
        cAcid.style.opacity = '0.3';
        cSalt.style.opacity = '1.0';
        cGas.style.opacity = '1.0';
        swapNotice.classList.remove('visible');
      }
    }

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

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

    function startTimer() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 3600);
    }

    function togglePlay() {
      isPlaying = !isPlaying;
      playBtn.textContent = isPlaying ? '⏸' : '▶';
      if (isPlaying) {
        startTimer();
      } else {
        clearInterval(timer);
      }
    }

    // Initialize
    updateView(0);
    startTimer();
  </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">
  <title>Filtration Apparatus</title>
  <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: #1e293b;
      display: flex;
      justify-content: center;
      align-items: center;
      min-height: 100vh;
      padding: 8px;
    }

    .diagram-svg {
      width: 100%;
      max-width: 600px;
      height: auto;
      display: block;
      overflow: visible;
    }

    /* Falling droplet animation */
    @keyframes dropFall {
      0% {
        transform: translateY(0);
        opacity: 0;
      }
      20% {
        opacity: 1;
      }
      80% {
        opacity: 1;
      }
      100% {
        transform: translateY(48px);
        opacity: 0;
      }
    }

    .falling-drop-1 {
      animation: dropFall 1.8s cubic-bezier(0.4, 0, 0.8, 1) infinite;
    }

    .falling-drop-2 {
      animation: dropFall 1.8s cubic-bezier(0.4, 0, 0.8, 1) infinite 0.9s;
    }

    /* Liquid ripple animation */
    @keyframes ripple {
      0% {
        r: 3px;
        opacity: 0.8;
        stroke-width: 1.5px;
      }
      100% {
        r: 22px;
        opacity: 0;
        stroke-width: 0.5px;
      }
    }

    .ripple-ring {
      animation: ripple 1.8s ease-out infinite 0.8s;
      transform-origin: 300px 395px;
    }

    .callout-label {
      font-size: 13px;
      font-weight: 700;
      fill: #0f172a;
    }

    .callout-sub {
      font-size: 11px;
      font-weight: 500;
      fill: #64748b;
    }
  </style>
</head>
<body>
  <svg class="diagram-svg" viewBox="0 0 600 480" xmlns="http://www.w3.org/2000/svg">
    <defs>
      
      <linearGradient id="filtrateGrad" x1="0%" y1="0%" x2="0%" y2="100%">
        <stop offset="0%" stop-color="#38bdf8" stop-opacity="0.35" />
        <stop offset="100%" stop-color="#0284c7" stop-opacity="0.7" />
      </linearGradient>

      
      <linearGradient id="glassShine" x1="0%" y1="0%" x2="100%" y2="0%">
        <stop offset="0%" stop-color="#ffffff" stop-opacity="0.6" />
        <stop offset="10%" stop-color="#ffffff" stop-opacity="0.1" />
        <stop offset="90%" stop-color="#ffffff" stop-opacity="0.0" />
        <stop offset="100%" stop-color="#ffffff" stop-opacity="0.4" />
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      <filter id="shadow" x="-5%" y="-5%" width="110%" height="115%" filterUnits="userSpaceOnUse">
        <feDropShadow dx="0" dy="2" stdDeviation="2" flood-color="#0f172a" flood-opacity="0.08" />
      </filter>
    </defs>

    
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          fill="url(#filtrateGrad)" />
    
    
    <ellipse cx="300" cy="395" rx="50" ry="5.5" fill="#bae6fd" stroke="#0284c7" stroke-width="1.2" />

    
    <ellipse class="ripple-ring" cx="300" cy="395" rx="10" ry="3" fill="none" stroke="#0284c7" />

    
    
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          fill="url(#glassShine)" 
          stroke="#475569" 
          stroke-width="2.5" 
          stroke-linejoin="round" />
    
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          fill="#f0f9ff" 
          stroke="#475569" 
          stroke-width="2" />

    
    <g>
      
      <path class="falling-drop-1" d="M 300 342 C 298 346, 297 349, 300 352 C 303 349, 302 346, 300 342 Z" 
            fill="#0284c7" />
      
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             fill-opacity="0.6" 
             stroke="#475569" 
             stroke-width="2.5" 
             stroke-linejoin="round" />
    
    <ellipse cx="300" cy="115" rx="85" ry="11" fill="#f1f5f9" stroke="#475569" stroke-width="2.5" />

    
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          fill="#fef3c7" 
          stroke="#d97706" 
          stroke-width="1.8" 
          filter="url(#shadow)" />
    
    
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      <circle cx="294" cy="222" r="3.5" />
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      <circle cx="290" cy="216" r="3.2" />
      <circle cx="297" cy="217" r="4" />
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      <circle cx="252" cy="145" r="3" fill="#64748b" />
      <text x="145" y="106" text-anchor="end" class="callout-label">Filter paper</text>
      <text x="145" y="122" text-anchor="end" class="callout-sub">traps insoluble solid</text>
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      <circle cx="314" cy="218" r="3" fill="#64748b" />
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      <text x="455" y="207" text-anchor="start" class="callout-sub">excess unreacted metal</text>
    </g>

    
    <g>
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      <circle cx="248" cy="190" r="3" fill="#64748b" />
      <text x="145" y="206" text-anchor="end" class="callout-label">Filter funnel</text>
      <text x="145" y="222" text-anchor="end" class="callout-sub">supports paper</text>
    </g>

    
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      <circle cx="262" cy="350" r="3" fill="#64748b" />
      <text x="145" y="366" text-anchor="end" class="callout-label">Conical flask</text>
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    <g>
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      <circle cx="342" cy="415" r="3" fill="#64748b" />
      <text x="455" y="411" text-anchor="start" class="callout-label">Filtrate</text>
      <text x="455" y="427" text-anchor="start" class="callout-sub">soluble salt solution</text>
    </g>
  </svg>
</body>
</html>

Preparation of Soluble Salts from Acid and Metal Reactions

<!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, sans-serif;
      background: #f8fafc;
      color: #1e293b;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    /* Controls */
    .controls {
      display: flex;
      gap: 8px;
      margin-bottom: 12px;
      width: 100%;
      max-width: 620px;
      justify-content: center;
    }
    .step-btn {
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      cursor: pointer;
      transition: all 0.25s ease;
    }
    .step-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.25);
    }

    /* Grid Layout */
    .stages-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      width: 100%;
      max-width: 620px;
    }
    @media (max-width: 520px) {
      .stages-grid { grid-template-columns: 1fr; }
    }

    /* Stage Cards */
    .stage-card {
      background: #ffffff;
      border-radius: 12px;
      border: 1px solid #e2e8f0;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      transition: opacity 0.3s ease, transform 0.3s ease;
    }
    .stage-card.dimmed {
      opacity: 0.35;
    }

    .stage-title {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .stage-badge {
      background: #e0f2fe;
      color: #0369a1;
      font-size: 11px;
      font-weight: 700;
      padding: 2px 7px;
      border-radius: 10px;
    }

    /* SVG Art */
    svg {
      width: 100%;
      height: auto;
      max-height: 230px;
      overflow: visible;
    }

    /* Steam Animation */
    @keyframes riseSteam {
      0% { transform: translateY(0) scaleX(1); opacity: 0; }
      40% { opacity: 0.6; }
      100% { transform: translateY(-16px) scaleX(1.3); opacity: 0; }
    }
    .steam-1 { animation: riseSteam 2.4s infinite ease-out; }
    .steam-2 { animation: riseSteam 2.4s infinite ease-out 0.8s; }
    .steam-3 { animation: riseSteam 2.4s infinite ease-out 1.6s; }

    /* Heat Flame Shimmer */
    @keyframes flamePulse {
      0%, 100% { transform: scale(1); opacity: 0.9; }
      50% { transform: scale(1.08, 0.95); opacity: 1; }
    }
    .flame {
      transform-origin: 100px 225px;
      animation: flamePulse 1.2s infinite ease-in-out;
    }

    /* Crystal Sparkle */
    @keyframes sparkle {
      0%, 100% { opacity: 0.4; }
      50% { opacity: 1; filter: drop-shadow(0 0 2px #38bdf8); }
    }
    .crystal-sparkle {
      animation: sparkle 2s infinite ease-in-out;
    }

    /* Micro-labels */
    .diag-label {
      font-size: 11px;
      font-weight: 600;
      fill: #475569;
    }
    .highlight-label {
      font-size: 11px;
      font-weight: 700;
      fill: #0284c7;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="step-btn active" onclick="setStage('all')">All Stages</button>
    <button class="step-btn" onclick="setStage('A')">1. Evaporate</button>
    <button class="step-btn" onclick="setStage('B')">2. Crystallise & Dry</button>
  </div>

  
  <div class="stages-grid">

    
    <div class="stage-card" id="cardA">
      <div class="stage-title">
        <span class="stage-badge">Stage 1</span>
        Evaporate to Saturation
      </div>

      <svg viewBox="0 0 220 240">
        
        <line x1="45" y1="180" x2="30" y2="235" stroke="#94a3b8" stroke-width="3.5" stroke-linecap="round" />
        <line x1="155" y1="180" x2="170" y2="235" stroke="#94a3b8" stroke-width="3.5" stroke-linecap="round" />
        <line x1="100" y1="180" x2="100" y2="235" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round" />
        <line x1="38" y1="180" x2="162" y2="180" stroke="#475569" stroke-width="4" stroke-linecap="round" />
        
        <line x1="48" y1="178" x2="152" y2="178" stroke="#cbd5e1" stroke-width="2" stroke-dasharray="3,3" />

        
        <g class="flame">
          <path d="M92,235 Q100,195 100,188 Q100,195 108,235 Z" fill="#38bdf8" />
          <path d="M96,235 Q100,205 100,198 Q100,205 104,235 Z" fill="#fef08a" />
        </g>

        
        <rect x="52" y="105" width="96" height="75" rx="3" fill="#e0f2fe" stroke="#64748b" stroke-width="2" />
        
        <rect x="54" y="125" width="92" height="53" fill="#bae6fd" opacity="0.8" />
        
        <circle cx="75" cy="155" r="2.5" fill="#ffffff" opacity="0.8" />
        <circle cx="85" cy="140" r="3.5" fill="#ffffff" opacity="0.8" />
        <circle cx="120" cy="160" r="2" fill="#ffffff" opacity="0.8" />
        <circle cx="112" cy="135" r="3" fill="#ffffff" opacity="0.8" />

        
        <path d="M42,105 Q100,135 158,105 Q100,110 42,105 Z" fill="#f1f5f9" stroke="#475569" stroke-width="2" />
        
        <path d="M48,107 Q100,130 152,107 Q100,112 48,107 Z" fill="#0284c7" opacity="0.75" />

        
        <g stroke="#94a3b8" stroke-width="2" fill="none" stroke-linecap="round">
          <path class="steam-1" d="M75,95 Q70,80 78,65 T72,50" />
          <path class="steam-2" d="M100,92 Q106,78 98,62 T104,46" />
          <path class="steam-3" d="M125,95 Q130,80 122,65 T128,50" />
        </g>

        
        <line x1="185" y1="20" x2="115" y2="110" stroke="#94a3b8" stroke-width="3" stroke-linecap="round" />

        
        <g transform="translate(140, 22)">
          <circle cx="28" cy="28" r="26" fill="#ffffff" stroke="#0284c7" stroke-width="2" />
          
          <line x1="42" y1="6" x2="14" y2="42" stroke="#64748b" stroke-width="4.5" stroke-linecap="round" />
          
          <polygon points="12,42 16,39 15,45" fill="#0284c7" class="crystal-sparkle" />
          <polygon points="17,46 22,43 20,49" fill="#38bdf8" class="crystal-sparkle" />
          <polygon points="18,36 22,34 20,39" fill="#0369a1" class="crystal-sparkle" />
          
          <circle cx="26" cy="46" r="1.5" fill="#38bdf8" />
          <circle cx="10" cy="36" r="1.5" fill="#38bdf8" />
        </g>

        
        <text x="100" y="152" text-anchor="middle" class="diag-label">Water bath</text>
        <text x="168" y="86" text-anchor="middle" class="highlight-label">Rod test: tiny crystals</text>
      </svg>
    </div>

    
    <div class="stage-card" id="cardB">
      <div class="stage-title">
        <span class="stage-badge">Stage 2</span>
        Cool &amp; Dry Crystals
      </div>

      <svg viewBox="0 0 220 240">
        
        <g transform="translate(0, 5)">
          
          <path d="M42,40 Q110,80 178,40 Q110,48 42,40 Z" fill="#f1f5f9" stroke="#475569" stroke-width="2" />
          
          <path d="M54,43 Q110,72 166,43 Q110,48 54,43 Z" fill="#bae6fd" opacity="0.6" />

          
          
          <polygon points="85,46 100,40 106,52 91,58" fill="#0284c7" stroke="#0369a1" stroke-width="1.2" />
          <polygon points="100,40 106,52 114,48 108,36" fill="#38bdf8" stroke="#0369a1" stroke-width="1.2" />
          
          <polygon points="105,50 125,42 133,56 113,64" fill="#0284c7" stroke="#0369a1" stroke-width="1.2" />
          <polygon points="125,42 133,56 142,50 134,36" fill="#38bdf8" stroke="#0369a1" stroke-width="1.2" />
          
          <polygon points="65,48 78,43 83,53 70,58" fill="#0369a1" stroke="#0284c7" stroke-width="1.2" />
          
          <polygon points="138,48 152,44 156,54 142,58" fill="#0284c7" stroke="#0369a1" stroke-width="1.2" />

          <text x="110" y="24" text-anchor="middle" class="diag-label">Cool slowly (room temp)</text>
          <text x="110" y="90" text-anchor="middle" class="highlight-label">Large crystals form</text>
        </g>

        
        <g stroke="#94a3b8" stroke-width="2" fill="none" stroke-linecap="round">
          <line x1="110" y1="104" x2="110" y2="124" />
          <path d="M105,119 L110,125 L115,119" stroke-linejoin="round" />
        </g>

        
        <g transform="translate(0, 130)">
          
          <ellipse cx="110" cy="72" rx="65" ry="18" fill="#f8fafc" stroke="#94a3b8" stroke-width="1.8" />
          
          
          <g transform="translate(5, 5)">
            <polygon points="90,60 102,54 107,63 95,69" fill="#0284c7" stroke="#0369a1" stroke-width="1" />
            <polygon points="102,54 107,63 115,59 110,50" fill="#38bdf8" stroke="#0369a1" stroke-width="1" />
            
            <polygon points="108,62 122,56 128,66 114,72" fill="#0284c7" stroke="#0369a1" stroke-width="1" />
            <polygon points="122,56 128,66 135,62 129,52" fill="#38bdf8" stroke="#0369a1" stroke-width="1" />
          </g>

          
          <g transform="translate(0, -14)">
            <ellipse cx="110" cy="50" rx="65" ry="18" fill="#ffffff" stroke="#0284c7" stroke-dasharray="4,3" stroke-width="1.8" opacity="0.9" />
            
            <path d="M75,20 L75,34 M72,30 L75,34 L78,30" stroke="#0284c7" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" fill="none" />
            <path d="M145,20 L145,34 M142,30 L145,34 L148,30" stroke="#0284c7" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" fill="none" />
          </g>

          <text x="110" y="100" text-anchor="middle" class="diag-label">Pat dry between filter paper</text>
        </g>
      </svg>
    </div>

  </div>

  <script>
    function setStage(stage) {
      const cardA = document.getElementById('cardA');
      const cardB = document.getElementById('cardB');
      const btns = document.querySelectorAll('.step-btn');
      
      btns.forEach(btn => btn.classList.remove('active'));

      if (stage === 'all') {
        btns[0].classList.add('active');
        cardA.classList.remove('dimmed');
        cardB.classList.remove('dimmed');
      } else if (stage === 'A') {
        btns[1].classList.add('active');
        cardA.classList.remove('dimmed');
        cardB.classList.add('dimmed');
      } else if (stage === 'B') {
        btns[2].classList.add('active');
        cardA.classList.add('dimmed');
        cardB.classList.remove('dimmed');
      }
    }
  </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; }
    html, body {
      width: 100%;
      height: 100%;
      background: transparent;
      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;
    }

    .container {
      width: 100%;
      max-width: 650px;
      padding: 8px 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 10px;
      width: 100%;
    }

    .col-card {
      background: #ffffff;
      border-radius: 12px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      position: relative;
      transition: box-shadow 0.3s ease;
    }

    .col-danger {
      border: 1.5px solid #fca5a5;
      background: #fffafa;
    }

    .col-ideal {
      border: 2px solid #10b981;
      background: #f0fdf4;
      box-shadow: 0 4px 16px rgba(16, 185, 129, 0.15);
    }

    .col-unreactive {
      border: 1.5px solid #cbd5e1;
      background: #f8fafc;
    }

    .badge {
      font-size: 12px;
      font-weight: 700;
      padding: 4px 8px;
      border-radius: 999px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 8px;
      white-space: nowrap;
    }

    .badge-danger { background: #fee2e2; color: #dc2626; }
    .badge-ideal { background: #dcfce7; color: #059669; }
    .badge-unreactive { background: #e2e8f0; color: #475569; }

    /* Tube Visualization Container */
    .tube-stage {
      width: 70px;
      height: 140px;
      position: relative;
      margin: 4px 0 8px 0;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Metal Symbols */
    .metals {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 2px;
    }

    .outcome-label {
      font-size: 11px;
      font-weight: 600;
      line-height: 1.25;
      margin-top: 2px;
    }

    .text-danger { color: #b91c1c; }
    .text-ideal { color: #047857; }
    .text-unreactive { color: #64748b; }

    /* Bubble Animations */
    @keyframes rise-violent {
      0% { transform: translateY(0) scale(0.6); opacity: 0.9; }
      50% { transform: translateY(-45px) scale(1.1); opacity: 1; }
      100% { transform: translateY(-90px) scale(1.4); opacity: 0; }
    }

    @keyframes rise-steady {
      0% { transform: translateY(0) scale(0.7); opacity: 0.3; }
      60% { opacity: 0.9; }
      100% { transform: translateY(-75px) scale(1); opacity: 0; }
    }

    @keyframes overflow-fizz {
      0%, 100% { transform: scale(1); opacity: 0.85; }
      50% { transform: scale(1.15) translateY(-2px); opacity: 1; }
    }

    .bubble-v1 { animation: rise-violent 0.8s infinite linear; }
    .bubble-v2 { animation: rise-violent 0.65s infinite linear 0.2s; }
    .bubble-v3 { animation: rise-violent 0.9s infinite linear 0.4s; }

    .bubble-s1 { animation: rise-steady 1.8s infinite ease-in; }
    .bubble-s2 { animation: rise-steady 2.0s infinite ease-in 0.6s; }
    .bubble-s3 { animation: rise-steady 1.6s infinite ease-in 1.1s; }

    .overflow-burst {
      animation: overflow-fizz 0.5s infinite ease-in-out;
      transform-origin: 35px 25px;
    }

    /* Subdued decorative flame for dangerous */
    @keyframes flame-pulse {
      0%, 100% { transform: scale(0.95); opacity: 0.85; }
      50% { transform: scale(1.05); opacity: 1; }
    }
    .flame-icon {
      animation: flame-pulse 0.7s infinite ease-in-out;
      transform-origin: center;
    }
  </style>
</head>
<body>

  <div class="container">
    <div class="grid">
      
      
      <div class="col-card col-danger">
        <span class="badge badge-danger">⚠️ Too Violent</span>
        <div class="tube-stage">
          <svg viewBox="0 0 70 140">
            
            <path d="M 18 35 L 52 35 L 52 112 A 17 17 0 0 1 18 112 Z" fill="#e0f2fe" />
            
            
            <g class="overflow-burst">
              <ellipse cx="35" cy="30" rx="20" ry="9" fill="#fecaca" />
              <circle cx="23" cy="22" r="4" fill="#ef4444" opacity="0.6"/>
              <circle cx="47" cy="20" r="3.5" fill="#f87171" opacity="0.7"/>
              <circle cx="35" cy="16" r="5" fill="#fca5a5" opacity="0.8"/>
            </g>

            
            <rect x="26" y="105" width="18" height="8" rx="2" fill="#94a3b8" />
            
            
            <circle class="bubble-v1" cx="30" cy="100" r="3.5" fill="#ef4444" />
            <circle class="bubble-v2" cx="40" cy="98" r="4.5" fill="#f97316" />
            <circle class="bubble-v3" cx="35" cy="95" r="3" fill="#ef4444" />
            <circle class="bubble-v1" cx="44" cy="92" r="4" fill="#ea580c" />
            <circle class="bubble-v2" cx="26" cy="96" r="3" fill="#f87171" />

            
            <path d="M 16 18 L 16 112 A 19 19 0 0 0 54 112 L 54 18" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
            <ellipse cx="35" cy="18" rx="19" ry="4" fill="none" stroke="#64748b" stroke-width="2.5" />
          </svg>
        </div>
        <div class="metals">K, Na</div>
        <div class="outcome-label text-danger">Hazardous<br>Explosive rate</div>
      </div>

      
      <div class="col-card col-ideal">
        <span class="badge badge-ideal">✨ Ideal Choice</span>
        <div class="tube-stage">
          <svg viewBox="0 0 70 140">
            
            <path d="M 18 45 L 52 45 L 52 112 A 17 17 0 0 1 18 112 Z" fill="#e0f2fe" />
            <ellipse cx="35" cy="45" rx="17" ry="4" fill="#bae6fd" />

            
            <rect x="25" y="106" width="20" height="9" rx="2" fill="#64748b" stroke="#334155" stroke-width="1"/>

            
            <circle class="bubble-s1" cx="31" cy="100" r="2.8" fill="#0284c7" />
            <circle class="bubble-s2" cx="39" cy="98" r="3.2" fill="#0284c7" />
            <circle class="bubble-s3" cx="35" cy="92" r="2.4" fill="#0369a1" />
            <circle class="bubble-s1" cx="42" cy="85" r="2.2" fill="#0284c7" />

            
            <path d="M 16 18 L 16 112 A 19 19 0 0 0 54 112 L 54 18" fill="none" stroke="#059669" stroke-width="2.5" stroke-linecap="round" />
            <ellipse cx="35" cy="18" rx="19" ry="4" fill="none" stroke="#059669" stroke-width="2.5" />
          </svg>
        </div>
        <div class="metals">Mg, Zn, Fe</div>
        <div class="outcome-label text-ideal">Safe, steady<br>H₂ bubbling</div>
      </div>

      
      <div class="col-card col-unreactive">
        <span class="badge badge-unreactive">✕ Unreactive</span>
        <div class="tube-stage">
          <svg viewBox="0 0 70 140">
            
            <path d="M 18 45 L 52 45 L 52 112 A 17 17 0 0 1 18 112 Z" fill="#f1f5f9" />
            <ellipse cx="35" cy="45" rx="17" ry="4" fill="#e2e8f0" />

            
            <rect x="24" y="110" width="22" height="9" rx="2" fill="#b45309" stroke="#78350f" stroke-width="1" />

            
            <path d="M 16 18 L 16 112 A 19 19 0 0 0 54 112 L 54 18" fill="none" stroke="#94a3b8" stroke-width="2" stroke-linecap="round" />
            <ellipse cx="35" cy="18" rx="19" ry="4" fill="none" stroke="#94a3b8" stroke-width="2" />
          </svg>
        </div>
        <div class="metals">Cu, Ag</div>
        <div class="outcome-label text-unreactive">No reaction<br>No salt formed</div>
      </div>

    </div>
  </div>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Acid and Metal Reaction</title>
  <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;
      min-height: 100vh;
      padding: 8px;
      user-select: none;
    }

    .scene-container {
      position: relative;
      width: 100%;
      max-width: 500px;
      height: 420px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-end;
    }

    /* Explanation bar at top */
    .status-bar {
      position: absolute;
      top: 6px;
      left: 50%;
      transform: translateX(-50%);
      width: 96%;
      max-width: 460px;
      min-height: 44px;
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 8px;
      padding: 8px 12px;
      font-size: 13px;
      line-height: 1.35;
      font-weight: 500;
      color: #334155;
      text-align: center;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.06);
      z-index: 20;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: opacity 0.5s ease, background-color 0.5s ease, border-color 0.5s ease;
    }
    .status-bar strong {
      color: #0284c7;
      margin-right: 4px;
    }

    /* Interactive Callout Badges */
    .callout {
      position: absolute;
      background: #ffffff;
      border: 1.5px solid #38bdf8;
      border-radius: 8px;
      padding: 6px 10px;
      font-size: 12px;
      font-weight: 600;
      color: #1e2945;
      box-shadow: 0 2px 8px rgba(2, 132, 199, 0.15);
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 6px;
      z-index: 10;
      transition: background-color 0.5s ease, border-color 0.5s ease, box-shadow 0.5s ease, color 0.5s ease;
      white-space: nowrap;
    }
    .callout:hover {
      border-color: #0284c7;
      box-shadow: 0 3px 10px rgba(2, 132, 199, 0.25);
    }
    .callout.active {
      background: #e0f2fe;
      border-color: #0284c7;
      color: #0369a1;
      box-shadow: 0 0 0 2.5px rgba(2, 132, 199, 0.3);
    }
    .badge-icon {
      font-size: 14px;
      line-height: 1;
    }

    /* Initial callout positions */
    #callout-gas {
      top: 68px;
      right: 12px;
    }
    #callout-metal {
      bottom: 120px;
      left: 10px;
    }
    #callout-heat {
      bottom: 24px;
      right: 18px;
    }

    /* SVG Apparatus */
    .apparatus-svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Pointer Lines */
    .pointer-line {
      stroke: #0284c7;
      stroke-width: 1.75;
      stroke-dasharray: 4 3;
      opacity: 0.5;
      transition: stroke 0.5s ease, stroke-width 0.5s ease, opacity 0.5s ease;
    }
    .pointer-line.active {
      stroke: #0284c7;
      stroke-width: 2.5;
      stroke-dasharray: none;
      opacity: 1;
    }

    /* Highlight pulse for interactive elements */
    .target-highlight {
      transition: filter 0.5s ease, opacity 0.5s ease;
    }
    .target-highlight.active {
      filter: drop-shadow(0 0 6px rgba(2, 132, 199, 0.7));
    }

    /* Heat Waves / Flame Animation */
    .flame-core {
      transform-origin: 240px 345px;
      animation: flicker 2.4s ease-in-out infinite alternate;
    }
    @keyframes flicker {
      0% { transform: scale(0.96, 0.96); opacity: 0.88; }
      100% { transform: scale(1.04, 1.08); opacity: 1; }
    }

    /* Gas bubbles rising */
    .bubble {
      animation: rise 2.8s ease-in infinite;
      opacity: 0;
    }
    .b1 { animation-delay: 0.1s; }
    .b2 { animation-delay: 0.8s; }
    .b3 { animation-delay: 1.5s; }
    .b4 { animation-delay: 2.2s; }
    .b5 { animation-delay: 0.5s; }
    .b6 { animation-delay: 1.2s; }
    .b7 { animation-delay: 1.9s; }

    @keyframes rise {
      0% { transform: translateY(0); opacity: 0; }
      20% { opacity: 0.9; }
      75% { opacity: 0.9; }
      100% { transform: translateY(-70px); opacity: 0; }
    }

    /* Mobile adjustments */
    @media (max-width: 400px) {
      .scene-container {
        height: 390px;
      }
      .callout {
        font-size: 11px;
        padding: 5px 8px;
      }
      #callout-gas {
        top: 60px;
        right: 6px;
      }
      #callout-metal {
        bottom: 115px;
        left: 6px;
      }
      #callout-heat {
        bottom: 18px;
        right: 8px;
      }
      .status-bar {
        font-size: 12px;
        padding: 6px 10px;
      }
    }
  </style>
</head>
<body>

<div class="scene-container" id="sceneContainer">
  
  <div class="status-bar" id="statusBar" aria-live="polite">
    <div><strong>Step 1:</strong> Dilute sulfuric acid is warmed gently with excess metal</div>
  </div>

  
  <div class="callout" id="callout-gas" onclick="selectItem('gas')" role="button" tabindex="0">
    <span class="badge-icon">🫧</span>
    <span>H₂ gas bubbles</span>
  </div>

  <div class="callout" id="callout-metal" onclick="selectItem('metal')" role="button" tabindex="0">
    <span class="badge-icon">⚪</span>
    <span>Excess unreacted metal</span>
  </div>

  <div class="callout" id="callout-heat" onclick="selectItem('heat')" role="button" tabindex="0">
    <span class="badge-icon">🔥</span>
    <span>Warmed gently</span>
  </div>

  
  <svg class="apparatus-svg" id="apparatusSvg" viewBox="0 0 480 380">
    <defs>
      
      <linearGradient id="acidGrad" x1="0%" y1="0%" x2="0%" y2="100%">
        <stop offset="0%" stop-color="#bae6fd" stop-opacity="0.65"/>
        <stop offset="100%" stop-color="#7dd3fc" stop-opacity="0.85"/>
      </linearGradient>

      
      <radialGradient id="heatGlow" cx="50%" cy="60%" r="50%">
        <stop offset="0%" stop-color="#fb923c" stop-opacity="0.85"/>
        <stop offset="60%" stop-color="#fdba74" stop-opacity="0.45"/>
        <stop offset="100%" stop-color="#fed7aa" stop-opacity="0"/>
      </radialGradient>

      
      <radialGradient id="granuleGrad" cx="35%" cy="35%" r="65%">
        <stop offset="0%" stop-color="#f1f5f9"/>
        <stop offset="100%" stop-color="#475569"/>
      </radialGradient>
    </defs>

    
    <line x1="165" y1="305" x2="315" y2="305" stroke="#475569" stroke-width="4" stroke-linecap="round"/>
    <line x1="180" y1="305" x2="155" y2="368" stroke="#64748b" stroke-width="3.5" stroke-linecap="round"/>
    <line x1="300" y1="305" x2="325" y2="368" stroke="#64748b" stroke-width="3.5" stroke-linecap="round"/>
    <line x1="240" y1="305" x2="240" y2="368" stroke="#94a3b8" stroke-width="3" stroke-linecap="round"/>

    
    <g id="target-heat" class="flame-core target-highlight">
      <ellipse cx="240" cy="342" rx="22" ry="18" fill="url(#heatGlow)"/>
      <path d="M232 352 Q240 326 240 326 Q240 326 248 352 Z" fill="#f97316"/>
      <path d="M236 352 Q240 334 240 334 Q240 334 244 352 Z" fill="#fef08a"/>
    </g>

    
    <ellipse cx="240" cy="140" rx="55" ry="9" fill="none" stroke="#94a3b8" stroke-width="2.5"/>

    
    <path d="M 186 210
             C 186 210, 185 295, 192 300
             C 200 305, 280 305, 288 300
             C 295 295, 294 210, 294 210
             Z"
          fill="url(#acidGrad)" id="liquid-body"/>

    <ellipse cx="240" cy="210" rx="54" ry="7.5" fill="#93c5fd" fill-opacity="0.6"/>

    
    <g id="target-gas" class="target-highlight">
      <circle class="bubble b1" cx="225" cy="275" r="4.5" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b2" cx="245" cy="280" r="3.5" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b3" cx="235" cy="265" r="5" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b4" cx="255" cy="270" r="3" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b5" cx="215" cy="282" r="3.8" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b6" cx="260" cy="278" r="4.2" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
      <circle class="bubble b7" cx="240" cy="288" r="3" fill="#ffffff" stroke="#0284c7" stroke-width="1.2"/>
    </g>

    
    <g id="target-metal" class="target-highlight">
      <ellipse cx="218" cy="298" rx="6.5" ry="4" fill="url(#granuleGrad)"/>
      <ellipse cx="232" cy="300" rx="8" ry="4.5" fill="url(#granuleGrad)"/>
      <ellipse cx="248" cy="299" rx="7" ry="4.2" fill="url(#granuleGrad)"/>
      <ellipse cx="262" cy="297" rx="6" ry="3.8" fill="url(#granuleGrad)"/>
      <ellipse cx="225" cy="295" rx="5.5" ry="3.5" fill="url(#granuleGrad)"/>
      <ellipse cx="240" cy="295" rx="7.5" ry="4" fill="url(#granuleGrad)"/>
      <ellipse cx="255" cy="294" rx="5" ry="3.2" fill="url(#granuleGrad)"/>
    </g>

    
    <path d="M 185 140 L 185 294 C 185 304, 295 304, 295 294 L 295 140"
          fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round"/>
    <path d="M 185 140 C 180 137, 175 137, 173 135" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round"/>
    <path d="M 173 135 C 180 145, 295 147, 295 140" fill="none" stroke="#64748b" stroke-width="2.5"/>

    
    <line x1="192" y1="230" x2="204" y2="230" stroke="#ffffff" stroke-width="1.5" opacity="0.8"/>
    <line x1="192" y1="250" x2="208" y2="250" stroke="#ffffff" stroke-width="1.5" opacity="0.8"/>
    <line x1="192" y1="270" x2="204" y2="270" stroke="#ffffff" stroke-width="1.5" opacity="0.8"/>

    
    <path id="ptr-gas" class="pointer-line" d="M 330 95 L 260 215" />
    <path id="ptr-metal" class="pointer-line" d="M 140 240 L 215 296" />
    <path id="ptr-heat" class="pointer-line" d="M 320 345 L 265 345" />
  </svg>
</div>

<script>
  const infoMap = {
    gas: '<strong>Bubbles of H₂ gas release:</strong> Rapid fizzing occurs as hydrogen gas is produced.',
    metal: '<strong>Excess unreacted metal:</strong> Settles on the bottom confirming all acid is neutralized.',
    heat: '<strong>Warmed gently:</strong> Increases collision energy to speed up the rate of reaction.'
  };

  const targetCoordinates = {
    gas: { x: 260, y: 220 },
    metal: { x: 215, y: 297 },
    heat: { x: 265, y: 345 }
  };

  function updateLeaderLines() {
    const svg = document.getElementById('apparatusSvg');
    if (!svg || !svg.getScreenCTM()) return;

    const screenCTM = svg.getScreenCTM();
    if (!screenCTM) return;
    const invCTM = screenCTM.inverse();
    const pt = svg.createSVGPoint();

    function getSvgPoint(domEl, anchorX, anchorY) {
      const rect = domEl.getBoundingClientRect();
      pt.x = rect.left + rect.width * anchorX;
      pt.y = rect.top + rect.height * anchorY;
      return pt.matrixTransform(invCTM);
    }

    const gasBadge = document.getElementById('callout-gas');
    const metalBadge = document.getElementById('callout-metal');
    const heatBadge = document.getElementById('callout-heat');

    if (gasBadge) {
      const start = getSvgPoint(gasBadge, 0, 0.5);
      const target = targetCoordinates.gas;
      document.getElementById('ptr-gas').setAttribute('d', `M ${start.x.toFixed(1)} ${start.y.toFixed(1)} L ${target.x} ${target.y}`);
    }

    if (metalBadge) {
      const start = getSvgPoint(metalBadge, 1, 0.5);
      const target = targetCoordinates.metal;
      document.getElementById('ptr-metal').setAttribute('d', `M ${start.x.toFixed(1)} ${start.y.toFixed(1)} L ${target.x} ${target.y}`);
    }

    if (heatBadge) {
      const start = getSvgPoint(heatBadge, 0, 0.5);
      const target = targetCoordinates.heat;
      document.getElementById('ptr-heat').setAttribute('d', `M ${start.x.toFixed(1)} ${start.y.toFixed(1)} L ${target.x} ${target.y}`);
    }
  }

  function selectItem(key) {
    document.querySelectorAll('.callout').forEach(el => el.classList.remove('active'));
    document.querySelectorAll('.pointer-line').forEach(el => el.classList.remove('active'));
    document.querySelectorAll('.target-highlight').forEach(el => el.classList.remove('active'));

    const btn = document.getElementById('callout-' + key);
    if (btn) btn.classList.add('active');

    const ptr = document.getElementById('ptr-' + key);
    if (ptr) ptr.classList.add('active');

    const target = document.getElementById('target-' + key);
    if (target) target.classList.add('active');

    const bar = document.getElementById('statusBar');
    if (bar && infoMap[key]) {
      bar.style.opacity = '0';
      setTimeout(() => {
        bar.innerHTML = '<div>' + infoMap[key] + '</div>';
        bar.style.opacity = '1';
      }, 250);
    }
  }

  // Keyboard accessibility
  document.querySelectorAll('.callout').forEach(btn => {
    btn.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' || e.key === ' ') {
        e.preventDefault();
        btn.click();
      }
    });
  });

  // Cycle sequence
  const keys = ['heat', 'gas', 'metal'];
  let cycleIdx = 0;
  let autoCycling = true;

  function cycle() {
    if (!autoCycling) return;
    selectItem(keys[cycleIdx]);
    cycleIdx = (cycleIdx + 1) % keys.length;
  }

  const timer = setInterval(cycle, 3600);

  // Stop auto-cycling on manual interaction
  document.querySelectorAll('.callout').forEach(btn => {
    btn.addEventListener('pointerdown', () => {
      autoCycling = false;
      clearInterval(timer);
    });
  });

  window.addEventListener('resize', updateLeaderLines);
  window.addEventListener('load', () => {
    updateLeaderLines();
    selectItem('heat');
  });

  // Initial call after DOM rendered
  requestAnimationFrame(() => {
    updateLeaderLines();
  });
</script>

</body>
</html>

UK-GCSE-SCIENCE-CHEM-CC-03-01

Aligned learning resources

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