<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Covalent Bonding: Electrostatic Attraction</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: #0f172a;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
      min-height: 100vh;
      overflow-x: hidden;
    }

    .container {
      width: 100%;
      max-width: 540px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    .toggle-bar {
      display: flex;
      gap: 6px;
      background: #cbd5e1;
      padding: 4px;
      border-radius: 24px;
      box-shadow: inset 0 1px 2px rgba(0,0,0,0.08);
    }

    .toggle-btn {
      border: 1px solid transparent;
      background: transparent;
      padding: 6px 18px;
      font-size: 14px;
      font-weight: 700;
      color: #1e293b;
      border-radius: 20px;
      cursor: pointer;
      transition: background-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
    }

    .toggle-btn:focus-visible {
      outline: 2px solid #0284c7;
      outline-offset: 2px;
    }

    .toggle-btn.active {
      background: #ffffff;
      color: #0369a1;
      border-color: #94a3b8;
      box-shadow: 0 2px 5px rgba(0,0,0,0.12);
    }

    .toggle-btn.active.btn-cl {
      color: #047857;
    }

    .svg-container {
      width: 100%;
      height: auto;
      aspect-ratio: 4 / 3;
      position: relative;
    }

    svg {
      width: 100%;
      height: 100%;
      display: block;
    }

    .shell {
      fill: none;
      stroke-dasharray: 5 4;
      transition: stroke 0.3s ease;
    }

    .shell-h {
      stroke: #0284c7;
      stroke-width: 2;
    }

    .shell-cl {
      stroke: #059669;
      stroke-width: 1.8;
    }

    .shell-cl-inner {
      stroke: #64748b;
      stroke-width: 1.2;
      stroke-dasharray: 3 3;
    }

    .overlap-zone {
      fill: rgba(2, 132, 199, 0.16);
      transition: fill 0.3s ease;
    }

    .cl-active .overlap-zone {
      fill: rgba(16, 185, 129, 0.18);
    }

    .force-arrow {
      stroke: #b91c1c;
      stroke-width: 3;
      stroke-linecap: round;
      fill: none;
      animation: pulse-force 2s infinite ease-in-out;
    }

    @keyframes pulse-force {
      0%, 100% { opacity: 1; stroke-width: 3; }
      50% { opacity: 0.55; stroke-width: 2.2; }
    }

    .label-badge {
      fill: #ffffff;
      stroke: #cbd5e1;
      stroke-width: 1;
      filter: drop-shadow(0 1px 2px rgba(0,0,0,0.06));
    }

    .label-force-txt {
      font-size: 12.5px;
      font-weight: 800;
      fill: #b91c1c;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .label-glue-txt {
      font-size: 12.5px;
      font-weight: 800;
      fill: #0369a1;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .cl-active .label-glue-txt {
      fill: #065f46;
    }

    .nucleus-txt {
      font-size: 13px;
      font-weight: 800;
      fill: #ffffff;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .e-txt {
      font-size: 11px;
      font-weight: 800;
      fill: #ffffff;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .caption {
      font-size: 12.5px;
      font-weight: 600;
      color: #334155;
      text-align: center;
      line-height: 1.4;
      padding: 0 8px;
    }

    .caption strong {
      color: #0f172a;
    }
  </style>
</head>
<body>

  <div class="container">
    <div class="toggle-bar">
      <button id="btnH" class="toggle-btn active" onclick="showMolecule('H2')">H₂ (Hydrogen)</button>
      <button id="btnCl" class="toggle-btn" onclick="showMolecule('Cl2')">Cl₂ (Chlorine)</button>
    </div>

    <div class="svg-container" id="diagramWrapper">
      <svg viewBox="0 0 460 345">
        <defs>
          
          <marker id="arrowL" markerWidth="7" markerHeight="7" refX="5" refY="3.5" orient="auto">
            <polygon points="0 0.8, 6.5 3.5, 0 6.2" fill="#b91c1c"/>
          </marker>
          <marker id="arrowR" markerWidth="7" markerHeight="7" refX="5" refY="3.5" orient="auto">
            <polygon points="0 0.8, 6.5 3.5, 0 6.2" fill="#b91c1c"/>
          </marker>
        </defs>

        
        <g id="groupLabelGlue" transform="translate(0, 5)">
          <path d="M 230,42 L 230,108" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="3 3"/>
          <circle cx="230" cy="110" r="3" fill="#0284c7"/>
          <rect class="label-badge" x="90" y="16" width="280" height="26" rx="13"/>
          <text x="230" y="29" class="label-glue-txt">Shared pair of electrons (electrostatic glue)</text>
        </g>

        
        <ellipse id="overlapGlow" class="overlap-zone" cx="230" cy="175" rx="44" ry="74"/>

        
        <g id="shellsGroup">
          
          <circle id="shellL" class="shell shell-h" cx="172" cy="175" r="78" />
          <circle id="shellR" class="shell shell-h" cx="288" cy="175" r="78" />

          
          <circle id="clInnerL1" class="shell shell-cl-inner" cx="160" cy="175" r="28" style="display:none;" />
          <circle id="clInnerL2" class="shell shell-cl-inner" cx="160" cy="175" r="52" style="display:none;" />
          <circle id="clInnerR1" class="shell shell-cl-inner" cx="300" cy="175" r="28" style="display:none;" />
          <circle id="clInnerR2" class="shell shell-cl-inner" cx="300" cy="175" r="52" style="display:none;" />
        </g>

        
        
        <line id="forceL" class="force-arrow" x1="172" y1="175" x2="216" y2="175" marker-end="url(#arrowL)" />
        
        <line id="forceR" class="force-arrow" x1="288" y1="175" x2="244" y2="175" marker-end="url(#arrowR)" />

        
        
        <circle id="nucL" cx="150" cy="175" r="17" fill="#dc2626" filter="drop-shadow(0 2px 4px rgba(220,38,38,0.35))"/>
        <text id="txtNucL" x="150" y="175" class="nucleus-txt">+ (H)</text>

        
        <circle id="nucR" cx="310" cy="175" r="17" fill="#dc2626" filter="drop-shadow(0 2px 4px rgba(220,38,38,0.35))"/>
        <text id="txtNucR" x="310" y="175" class="nucleus-txt">+ (H)</text>

        
        <g id="sharedElectrons">
          <circle cx="230" cy="155" r="8" fill="#0284c7" filter="drop-shadow(0 1px 3px rgba(2,132,199,0.4))"/>
          <text x="230" y="155" class="e-txt">e⁻</text>

          <circle cx="230" cy="195" r="8" fill="#0284c7" filter="drop-shadow(0 1px 3px rgba(2,132,199,0.4))"/>
          <text x="230" y="195" class="e-txt">e⁻</text>
        </g>

        
        <g id="clElectrons" style="display:none;">
          
          <circle cx="82" cy="175" r="6.5" fill="#059669"/><text x="82" y="175" class="e-txt">e⁻</text>
          <circle cx="116" cy="108" r="6.5" fill="#059669"/><text x="116" y="108" class="e-txt">e⁻</text>
          <circle cx="160" cy="97" r="6.5" fill="#059669"/><text x="160" y="97" class="e-txt">e⁻</text>
          <circle cx="116" cy="242" r="6.5" fill="#059669"/><text x="116" y="242" class="e-txt">e⁻</text>
          <circle cx="160" cy="253" r="6.5" fill="#059669"/><text x="160" y="253" class="e-txt">e⁻</text>
          
          
          <circle cx="378" cy="175" r="6.5" fill="#059669"/><text x="378" y="175" class="e-txt">e⁻</text>
          <circle cx="344" cy="108" r="6.5" fill="#059669"/><text x="344" y="108" class="e-txt">e⁻</text>
          <circle cx="300" cy="97" r="6.5" fill="#059669"/><text x="300" y="97" class="e-txt">e⁻</text>
          <circle cx="344" cy="242" r="6.5" fill="#059669"/><text x="344" y="242" class="e-txt">e⁻</text>
          <circle cx="300" cy="253" r="6.5" fill="#059669"/><text x="300" y="253" class="e-txt">e⁻</text>
        </g>

        
        <g id="groupLabelForce" transform="translate(0, -4)">
          
          <path d="M 194,302 L 194,185" stroke="#b91c1c" stroke-width="1.2" stroke-dasharray="2 3"/>
          <path d="M 266,302 L 266,185" stroke="#b91c1c" stroke-width="1.2" stroke-dasharray="2 3"/>
          <rect class="label-badge" x="120" y="302" width="220" height="26" rx="13"/>
          <text x="230" y="315" class="label-force-txt">Electrostatic Attraction Forces</text>
        </g>
      </svg>
    </div>

    <p class="caption">
      <strong>Covalent Bond:</strong> The simultaneous electrostatic pull from <strong>both positive nuclei (+)</strong> holding the <strong>shared electron pair (e⁻)</strong> together.
    </p>
  </div>

  <script>
    function showMolecule(type) {
      const btnH = document.getElementById('btnH');
      const btnCl = document.getElementById('btnCl');
      const wrapper = document.getElementById('diagramWrapper');
      
      const shellL = document.getElementById('shellL');
      const shellR = document.getElementById('shellR');
      const nucL = document.getElementById('nucL');
      const nucR = document.getElementById('nucR');
      const txtNucL = document.getElementById('txtNucL');
      const txtNucR = document.getElementById('txtNucR');
      const forceL = document.getElementById('forceL');
      const forceR = document.getElementById('forceR');
      
      const clInners = [
        document.getElementById('clInnerL1'),
        document.getElementById('clInnerL2'),
        document.getElementById('clInnerR1'),
        document.getElementById('clInnerR2')
      ];
      const clElectrons = document.getElementById('clElectrons');

      if (type === 'H2') {
        btnH.classList.add('active');
        btnCl.classList.remove('active', 'btn-cl');
        wrapper.classList.remove('cl-active');

        shellL.setAttribute('cx', '172');
        shellL.setAttribute('r', '78');
        shellL.className.baseVal = 'shell shell-h';

        shellR.setAttribute('cx', '288');
        shellR.setAttribute('r', '78');
        shellR.className.baseVal = 'shell shell-h';

        nucL.setAttribute('cx', '150');
        txtNucL.setAttribute('x', '150');
        txtNucL.textContent = '+ (H)';

        nucR.setAttribute('cx', '310');
        txtNucR.setAttribute('x', '310');
        txtNucR.textContent = '+ (H)';

        forceL.setAttribute('x1', '168');
        forceL.setAttribute('x2', '216');

        forceR.setAttribute('x1', '292');
        forceR.setAttribute('x2', '244');

        clInners.forEach(el => el.style.display = 'none');
        clElectrons.style.display = 'none';
      } else {
        btnCl.classList.add('active', 'btn-cl');
        btnH.classList.remove('active');
        wrapper.classList.add('cl-active');

        shellL.setAttribute('cx', '160');
        shellL.setAttribute('r', '78');
        shellL.className.baseVal = 'shell shell-cl';

        shellR.setAttribute('cx', '300');
        shellR.setAttribute('r', '78');
        shellR.className.baseVal = 'shell shell-cl';

        nucL.setAttribute('cx', '160');
        txtNucL.setAttribute('x', '160');
        txtNucL.textContent = '+ (Cl)';

        nucR.setAttribute('cx', '300');
        txtNucR.setAttribute('x', '300');
        txtNucR.textContent = '+ (Cl)';

        forceL.setAttribute('x1', '178');
        forceL.setAttribute('x2', '216');

        forceR.setAttribute('x1', '282');
        forceR.setAttribute('x2', '244');

        clInners.forEach(el => el.style.display = 'inline');
        clElectrons.style.display = 'inline';
      }
    }
  </script>
</body>
</html>

Electrostatic Forces in Chemical Bonding

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      width: 100%;
      font-family: system-ui, -apple-system, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 12px;
      user-select: none;
    }

    .header-labels {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 12px 18px;
      margin-bottom: 10px;
      font-size: 13px;
      font-weight: 600;
    }

    .legend-item {
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    .ion-sample {
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: radial-gradient(circle at 35% 35%, #ffd480, #f59e0b);
      border: 1.5px solid #d97706;
      color: #78350f;
      font-size: 11px;
      font-weight: 800;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .electron-sample {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #0284c7;
      box-shadow: 0 0 6px rgba(2, 132, 199, 0.8);
    }

    .force-sample {
      width: 16px;
      height: 2px;
      background: #ef4444;
      position: relative;
    }
    .force-sample::after {
      content: '';
      position: absolute;
      right: 0;
      top: -3px;
      border: 4px solid transparent;
      border-left-color: #ef4444;
    }

    .canvas-container {
      position: relative;
      width: 100%;
      max-width: 540px;
      height: 300px;
      border-radius: 12px;
      overflow: hidden;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
    }

    canvas {
      display: block;
      width: 100%;
      height: 100%;
    }

    .controls {
      display: flex;
      justify-content: center;
      gap: 10px;
      margin-top: 10px;
      width: 100%;
      max-width: 540px;
    }

    .btn {
      appearance: none;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      padding: 6px 14px;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 600;
      color: #334155;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background 0.15s, border-color 0.15s;
    }
    .btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }
    .btn.active {
      background: #e0f2fe;
      border-color: #0284c7;
      color: #0369a1;
    }
  </style>
</head>
<body>

  <div class="header-labels">
    <div class="legend-item">
      <div class="ion-sample">+</div>
      <span>Metal Ion (Cu²⁺)</span>
    </div>
    <div class="legend-item">
      <div class="electron-sample"></div>
      <span>Delocalised e⁻ Sea</span>
    </div>
    <div class="legend-item">
      <div class="force-sample"></div>
      <span>Electrostatic Attraction</span>
    </div>
  </div>

  <div class="canvas-container" id="container">
    <canvas id="diagramCanvas"></canvas>
  </div>

  <div class="controls">
    <button class="btn active" id="forceBtn" onclick="toggleForces()">
      <span>⚡ Attraction Forces</span>
    </button>
    <button class="btn" id="playBtn" onclick="togglePlay()">
      <span id="playIcon">⏸</span> <span id="playText">Pause</span>
    </button>
  </div>

  <script>
    const canvas = document.getElementById('diagramCanvas');
    const ctx = canvas.getContext('2d');
    const container = document.getElementById('container');
    const forceBtn = document.getElementById('forceBtn');
    const playIcon = document.getElementById('playIcon');
    const playText = document.getElementById('playText');

    let showForces = true;
    let isPlaying = true;
    let animId = null;

    let width = 0;
    let height = 0;
    let dpr = window.devicePixelRatio || 1;

    const COLS = 4;
    const ROWS = 3;
    const ions = [];
    const NUM_ELECTRONS = 55;
    const electrons = [];

    function resize() {
      const rect = container.getBoundingClientRect();
      width = rect.width;
      height = rect.height;
      canvas.width = width * dpr;
      canvas.height = height * dpr;
      ctx.scale(dpr, dpr);
      initIons();
    }

    function initIons() {
      ions.length = 0;
      const marginX = width * 0.14;
      const marginY = height * 0.18;
      const stepX = (width - marginX * 2) / (COLS - 1);
      const stepY = (height - marginY * 2) / (ROWS - 1);
      const radius = Math.min(width, height) * 0.085;

      for (let r = 0; r < ROWS; r++) {
        for (let c = 0; c < COLS; c++) {
          ions.push({
            x: marginX + c * stepX,
            y: marginY + r * stepY,
            radius: radius
          });
        }
      }
    }

    function initElectrons() {
      electrons.length = 0;
      for (let i = 0; i < NUM_ELECTRONS; i++) {
        electrons.push({
          x: Math.random() * (width || 400),
          y: Math.random() * (height || 260),
          vx: (Math.random() - 0.5) * 1.8,
          vy: (Math.random() - 0.5) * 1.8,
          size: 2.8 + Math.random() * 1.2
        });
      }
    }

    function toggleForces() {
      showForces = !showForces;
      forceBtn.classList.toggle('active', showForces);
    }

    function togglePlay() {
      isPlaying = !isPlaying;
      playIcon.textContent = isPlaying ? '⏸' : '▶';
      playText.textContent = isPlaying ? 'Pause' : 'Play';
      if (isPlaying) {
        lastTime = performance.now();
        animLoop();
      }
    }

    function updateElectrons(dt) {
      const speedMultiplier = 60 * dt;
      for (let e of electrons) {
        e.x += e.vx * speedMultiplier;
        e.y += e.vy * speedMultiplier;

        // Wrap around borders for continuous fluid flow
        if (e.x < 0) e.x = width;
        if (e.x > width) e.x = 0;
        if (e.y < 0) e.y = height;
        if (e.y > height) e.y = 0;

        // Gentle deflection from ion centers (ions are positive spheres, e- flow between)
        for (let ion of ions) {
          const dx = e.x - ion.x;
          const dy = e.y - ion.y;
          const distSq = dx * dx + dy * dy;
          const minDist = ion.radius * 0.75;
          if (distSq < minDist * minDist && distSq > 0) {
            const dist = Math.sqrt(distSq);
            const nx = dx / dist;
            const ny = dy / dist;
            e.x = ion.x + nx * minDist;
            e.y = ion.y + ny * minDist;
            // Reflect velocity slightly with randomness
            const dot = e.vx * nx + e.vy * ny;
            e.vx = (e.vx - 1.8 * dot * nx) + (Math.random() - 0.5) * 0.2;
            e.vy = (e.vy - 1.8 * dot * ny) + (Math.random() - 0.5) * 0.2;
            // Cap speed
            const speed = Math.hypot(e.vx, e.vy);
            if (speed > 2.2) {
              e.vx = (e.vx / speed) * 2.2;
              e.vy = (e.vy / speed) * 2.2;
            }
          }
        }
      }
    }

    function draw() {
      ctx.clearRect(0, 0, width, height);

      // 1. Electron sea background cloud
      const seaGrad = ctx.createRadialGradient(width / 2, height / 2, 40, width / 2, height / 2, width * 0.6);
      seaGrad.addColorStop(0, 'rgba(224, 242, 254, 0.45)');
      seaGrad.addColorStop(1, 'rgba(240, 249, 255, 0.2)');
      ctx.fillStyle = seaGrad;
      ctx.fillRect(0, 0, width, height);

      // 2. Electrostatic Attraction vectors
      if (showForces) {
        ctx.save();
        for (let ion of ions) {
          for (let e of electrons) {
            const dx = e.x - ion.x;
            const dy = e.y - ion.y;
            const dist = Math.hypot(dx, dy);
            if (dist > ion.radius * 0.7 && dist < ion.radius * 2.1) {
              const alpha = (1 - (dist - ion.radius * 0.7) / (ion.radius * 1.4)) * 0.4;
              ctx.strokeStyle = `rgba(239, 68, 68, ${alpha})`;
              ctx.lineWidth = 1.2;
              ctx.beginPath();
              ctx.moveTo(ion.x, ion.y);
              ctx.lineTo(e.x, e.y);
              ctx.stroke();

              // Arrow tip halfway
              const midX = ion.x + dx * 0.55;
              const midY = ion.y + dy * 0.55;
              const angle = Math.atan2(dy, dx);
              ctx.fillStyle = `rgba(239, 68, 68, ${alpha * 1.4})`;
              ctx.beginPath();
              ctx.arc(midX, midY, 1.8, 0, Math.PI * 2);
              ctx.fill();
            }
          }
        }
        ctx.restore();
      }

      // 3. Positive Metal Ions (Lattice Grid)
      for (let ion of ions) {
        ctx.save();
        
        // Shadow/glow
        ctx.shadowColor = 'rgba(217, 119, 6, 0.25)';
        ctx.shadowBlur = 8;
        ctx.shadowOffsetY = 2;

        // Gradient Fill
        const grad = ctx.createRadialGradient(
          ion.x - ion.radius * 0.3,
          ion.y - ion.radius * 0.3,
          ion.radius * 0.1,
          ion.x,
          ion.y,
          ion.radius
        );
        grad.addColorStop(0, '#fef08a');
        grad.addColorStop(0.5, '#f59e0b');
        grad.addColorStop(1, '#d97706');

        ctx.fillStyle = grad;
        ctx.beginPath();
        ctx.arc(ion.x, ion.y, ion.radius, 0, Math.PI * 2);
        ctx.fill();

        ctx.shadowBlur = 0;
        ctx.shadowOffsetY = 0;
        ctx.strokeStyle = '#b45309';
        ctx.lineWidth = 1.5;
        ctx.stroke();

        // Plus symbol
        ctx.fillStyle = '#ffffff';
        ctx.font = `bold ${Math.round(ion.radius * 0.9)}px system-ui, sans-serif`;
        ctx.textAlign = 'center';
        ctx.textBaseline = 'middle';
        ctx.fillText('+', ion.x, ion.y + 0.5);

        ctx.restore();
      }

      // 4. Delocalised Electrons
      ctx.save();
      for (let e of electrons) {
        // Glow
        ctx.fillStyle = 'rgba(56, 189, 248, 0.4)';
        ctx.beginPath();
        ctx.arc(e.x, e.y, e.size * 2, 0, Math.PI * 2);
        ctx.fill();

        // Core
        ctx.fillStyle = '#0284c7';
        ctx.beginPath();
        ctx.arc(e.x, e.y, e.size, 0, Math.PI * 2);
        ctx.fill();

        // Minus sign on slightly larger dots
        if (e.size > 3.2) {
          ctx.fillStyle = '#ffffff';
          ctx.fillRect(e.x - 1.5, e.y - 0.4, 3, 0.8);
        }
      }
      ctx.restore();
    }

    let lastTime = performance.now();
    function animLoop(now = performance.now()) {
      const dt = Math.min((now - lastTime) / 1000, 0.1);
      lastTime = now;

      if (isPlaying) {
        updateElectrons(dt);
      }
      draw();

      if (isPlaying) {
        animId = requestAnimationFrame(animLoop);
      }
    }

    window.addEventListener('resize', resize);
    resize();
    initElectrons();
    animLoop();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: #ffffff;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .header-title {
      font-size: 16px;
      font-weight: 700;
      color: #0f172a;
      text-align: center;
      margin-bottom: 10px;
    }

    .grid-container {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
      max-width: 660px;
    }

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

    .model-card {
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      cursor: pointer;
      transition: box-shadow 0.2s ease, border-color 0.2s ease;
      user-select: none;
    }

    .model-card.active, .model-card:hover {
      border-color: #3b82f6;
      box-shadow: 0 4px 12px rgba(59, 130, 246, 0.12);
    }

    .badge {
      font-size: 13px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      padding: 3px 10px;
      border-radius: 20px;
      margin-bottom: 8px;
    }

    .badge-ionic {
      background: #ede9fe;
      color: #6d28d9;
    }

    .badge-covalent {
      background: #e0f2fe;
      color: #0369a1;
    }

    .badge-metallic {
      background: #fef3c7;
      color: #b45309;
    }

    .diagram-svg {
      width: 100%;
      max-width: 170px;
      height: 110px;
      margin: 4px 0;
    }

    .components-box {
      width: 100%;
      display: flex;
      flex-direction: column;
      gap: 4px;
      margin-top: 6px;
      font-size: 12px;
    }

    .comp-row {
      display: flex;
      align-items: center;
      gap: 6px;
      padding: 3px 6px;
      border-radius: 6px;
      background: #ffffff;
      border: 1px solid #f1f5f9;
    }

    .symbol-pill {
      font-size: 11px;
      font-weight: 800;
      width: 18px;
      height: 18px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: 50%;
      flex-shrink: 0;
    }

    .pill-pos {
      background: #fee2e2;
      color: #dc2626;
    }

    .pill-neg {
      background: #dbeafe;
      color: #2563eb;
    }

    .comp-text {
      font-size: 11.5px;
      font-weight: 600;
      color: #334155;
      line-height: 1.2;
    }

    /* SVG internal styles & animations */
    .force-line {
      stroke: #dc2626;
      stroke-width: 1.5;
      stroke-dasharray: 3 2;
      animation: dashMove 1.5s linear infinite;
    }

    .electron-sea {
      fill: #e0f2fe;
      opacity: 0.7;
    }

    .deloc-e {
      animation: drift 3s ease-in-out infinite alternate;
    }

    .deloc-e:nth-child(2) { animation-delay: -0.8s; }
    .deloc-e:nth-child(3) { animation-delay: -1.6s; }
    .deloc-e:nth-child(4) { animation-delay: -2.2s; }

    @keyframes dashMove {
      to { stroke-dashoffset: -10; }
    }

    @keyframes drift {
      from { transform: translate(0, 0); }
      to { transform: translate(3px, -2px); }
    }
  </style>
</head>
<body>

  <div class="header-title">The Three Electrostatic Models</div>

  <div class="grid-container">
    
    
    <div class="model-card active" onclick="selectCard(this)">
      <span class="badge badge-ionic">Ionic</span>
      <svg class="diagram-svg" viewBox="0 0 160 110">
        
        <line x1="45" y1="55" x2="115" y2="55" class="force-line" />
        <line x1="72" y1="50" x2="68" y2="55" stroke="#dc2626" stroke-width="1.5" stroke-linecap="round" />
        <line x1="72" y1="60" x2="68" y2="55" stroke="#dc2626" stroke-width="1.5" stroke-linecap="round" />
        <line x1="88" y1="50" x2="92" y2="55" stroke="#dc2626" stroke-width="1.5" stroke-linecap="round" />
        <line x1="88" y1="60" x2="92" y2="55" stroke="#dc2626" stroke-width="1.5" stroke-linecap="round" />

        
        <circle cx="45" cy="55" r="22" fill="#ef4444" opacity="0.15" />
        <circle cx="45" cy="55" r="18" fill="#ef4444" />
        <text x="45" y="60" font-size="16" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        
        <circle cx="115" cy="55" r="28" fill="#3b82f6" opacity="0.15" />
        <circle cx="115" cy="55" r="24" fill="#3b82f6" />
        <text x="115" y="61" font-size="18" font-weight="bold" fill="#ffffff" text-anchor="middle">−</text>
      </svg>
      <div class="components-box">
        <div class="comp-row">
          <span class="symbol-pill pill-pos">+</span>
          <span class="comp-text">Metal Cation</span>
        </div>
        <div class="comp-row">
          <span class="symbol-pill pill-neg">−</span>
          <span class="comp-text">Non-metal Anion</span>
        </div>
      </div>
    </div>

    
    <div class="model-card" onclick="selectCard(this)">
      <span class="badge badge-covalent">Covalent</span>
      <svg class="diagram-svg" viewBox="0 0 160 110">
        
        <circle cx="58" cy="55" r="32" fill="none" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3 2" />
        <circle cx="102" cy="55" r="32" fill="none" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3 2" />

        
        <line x1="42" y1="55" x2="74" y2="55" class="force-line" />
        <line x1="118" y1="55" x2="86" y2="55" class="force-line" />

        
        <circle cx="42" cy="55" r="12" fill="#ef4444" />
        <text x="42" y="59" font-size="12" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        <circle cx="118" cy="55" r="12" fill="#ef4444" />
        <text x="118" y="59" font-size="12" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        
        <circle cx="80" cy="46" r="4.5" fill="#3b82f6" />
        <text x="80" y="49" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">−</text>
        <circle cx="80" cy="64" r="4.5" fill="#3b82f6" />
        <text x="80" y="67" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">−</text>
      </svg>
      <div class="components-box">
        <div class="comp-row">
          <span class="symbol-pill pill-pos">+</span>
          <span class="comp-text">Positive Nuclei</span>
        </div>
        <div class="comp-row">
          <span class="symbol-pill pill-neg">−</span>
          <span class="comp-text">Shared Electron Pair</span>
        </div>
      </div>
    </div>

    
    <div class="model-card" onclick="selectCard(this)">
      <span class="badge badge-metallic">Metallic</span>
      <svg class="diagram-svg" viewBox="0 0 160 110">
        
        <rect x="18" y="20" width="124" height="70" rx="10" class="electron-sea" />

        
        <g class="deloc-e">
          <circle cx="34" cy="32" r="3.5" fill="#2563eb" />
          <circle cx="80" cy="27" r="3.5" fill="#2563eb" />
          <circle cx="126" cy="34" r="3.5" fill="#2563eb" />
          <circle cx="48" cy="55" r="3.5" fill="#2563eb" />
          <circle cx="112" cy="55" r="3.5" fill="#2563eb" />
          <circle cx="80" cy="83" r="3.5" fill="#2563eb" />
        </g>

        
        
        <circle cx="45" cy="40" r="11" fill="#ef4444" />
        <text x="45" y="44" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        <circle cx="80" cy="40" r="11" fill="#ef4444" />
        <text x="80" y="44" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        <circle cx="115" cy="40" r="11" fill="#ef4444" />
        <text x="115" y="44" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        
        <circle cx="45" cy="70" r="11" fill="#ef4444" />
        <text x="45" y="74" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        <circle cx="80" cy="70" r="11" fill="#ef4444" />
        <text x="80" y="74" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>

        <circle cx="115" cy="70" r="11" fill="#ef4444" />
        <text x="115" y="74" font-size="11" font-weight="bold" fill="#ffffff" text-anchor="middle">+</text>
      </svg>
      <div class="components-box">
        <div class="comp-row">
          <span class="symbol-pill pill-pos">+</span>
          <span class="comp-text">Metal Cations</span>
        </div>
        <div class="comp-row">
          <span class="symbol-pill pill-neg">−</span>
          <span class="comp-text">Delocalised Electrons</span>
        </div>
      </div>
    </div>

  </div>

  <script>
    function selectCard(card) {
      document.querySelectorAll('.model-card').forEach(c => c.classList.remove('active'));
      card.classList.add('active');
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      background-color: #f8f9fa;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 16px 12px;
      overflow-x: hidden;
    }

    .nav-tabs {
      display: flex;
      gap: 6px;
      width: 100%;
      max-width: 420px;
      background: #e2e8f0;
      padding: 4px;
      border-radius: 12px;
    }

    .tab-btn {
      flex: 1;
      border: none;
      background: transparent;
      padding: 8px 4px;
      font-size: 14px;
      font-weight: 700;
      color: #64748b;
      border-radius: 8px;
      cursor: pointer;
      transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
      text-align: center;
    }

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

    .stage-container {
      position: relative;
      width: 100%;
      max-width: 420px;
      height: 220px;
      background: #ffffff;
      border-radius: 16px;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
      border: 1px solid #e2e8f0;
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
      margin: 12px 0;
    }

    .field-lines {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
    }

    .charge-track {
      position: relative;
      width: 100%;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .charge {
      position: absolute;
      width: 64px;
      height: 64px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 32px;
      font-weight: 800;
      color: #ffffff;
      z-index: 10;
      transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    }

    .charge-pos {
      background: radial-gradient(circle at 35% 35%, #ff5252, #dc2626);
      box-shadow: 0 0 20px rgba(239, 68, 68, 0.45), 0 4px 10px rgba(220, 38, 38, 0.3);
    }

    .charge-neg {
      background: radial-gradient(circle at 35% 35%, #38bdf8, #0284c7);
      box-shadow: 0 0 20px rgba(56, 189, 248, 0.45), 0 4px 10px rgba(2, 132, 199, 0.3);
    }

    .force-group {
      position: absolute;
      display: flex;
      align-items: center;
      justify-content: center;
      pointer-events: none;
      z-index: 5;
      transition: all 0.4s ease;
    }

    .force-arrow {
      height: 4px;
      background: #10b981;
      position: relative;
      transition: width 0.3s ease, background 0.3s ease;
      border-radius: 2px;
    }

    .force-arrow.repel {
      background: #f59e0b;
    }

    .arrow-head {
      position: absolute;
      top: 50%;
      width: 0;
      height: 0;
      border-top: 6px solid transparent;
      border-bottom: 6px solid transparent;
      transform: translateY(-50%);
    }

    .arrow-head-left {
      left: -2px;
      border-right: 10px solid #10b981;
    }

    .arrow-head-right {
      right: -2px;
      border-left: 10px solid #10b981;
    }

    .force-arrow.repel .arrow-head-left {
      border-right-color: #f59e0b;
    }

    .force-arrow.repel .arrow-head-right {
      border-left-color: #f59e0b;
    }

    .status-badge {
      position: absolute;
      top: 14px;
      background: #f1f5f9;
      color: #1e2945;
      font-size: 14px;
      font-weight: 700;
      padding: 4px 14px;
      border-radius: 20px;
      border: 1px solid #cbd5e1;
      display: flex;
      align-items: center;
      gap: 6px;
      z-index: 20;
    }

    .dot-indicator {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #10b981;
    }

    .dot-indicator.repel {
      background: #f59e0b;
    }

    .controls-card {
      width: 100%;
      max-width: 420px;
      background: #ffffff;
      border-radius: 14px;
      border: 1px solid #e2e8f0;
      padding: 12px 16px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .slider-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
    }

    .slider-label {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      min-width: 60px;
    }

    input[type=range] {
      flex: 1;
      accent-color: #2563eb;
      height: 6px;
      background: #e2e8f0;
      border-radius: 4px;
      outline: none;
      cursor: pointer;
    }

    .legend-row {
      display: flex;
      justify-content: space-around;
      font-size: 13px;
      color: #64748b;
      font-weight: 600;
      padding-top: 4px;
      border-top: 1px solid #f1f5f9;
    }

    .legend-item {
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .circle-mini {
      width: 10px;
      height: 10px;
      border-radius: 50%;
    }
  </style>
</head>
<body>

  <div class="nav-tabs">
    <button class="tab-btn active" onclick="setMode('opposite')">+ &minus; Opposite</button>
    <button class="tab-btn" onclick="setMode('pos-pos')">+ + Like</button>
    <button class="tab-btn" onclick="setMode('neg-neg')">&minus; &minus; Like</button>
  </div>

  <div class="stage-container">
    <svg class="field-lines" id="svgCanvas"></svg>

    <div class="status-badge" id="statusBadge">
      <span class="dot-indicator" id="statusDot"></span>
      <span id="statusText">Attraction (Pull)</span>
    </div>

    <div class="charge-track">
      <div class="charge charge-pos" id="chargeLeft">+</div>
      <div class="force-group" id="forceGroup">
        <div class="force-arrow" id="forceArrowLeft">
          <div class="arrow-head" id="headLeft"></div>
        </div>
        <div style="width: 24px;"></div>
        <div class="force-arrow" id="forceArrowRight">
          <div class="arrow-head" id="headRight"></div>
        </div>
      </div>
      <div class="charge charge-neg" id="chargeRight">&minus;</div>
    </div>
  </div>

  <div class="controls-card">
    <div class="slider-row">
      <span class="slider-label">Distance</span>
      <input type="range" id="distSlider" min="90" max="150" value="115" oninput="updatePositions()">
    </div>
    <div class="legend-row">
      <div class="legend-item">
        <span class="circle-mini" style="background:#ef4444;"></span>
        <span>Positive (+)</span>
      </div>
      <div class="legend-item">
        <span class="circle-mini" style="background:#0284c7;"></span>
        <span>Negative (&minus;)</span>
      </div>
    </div>
  </div>

  <script>
    let currentMode = 'opposite';
    const slider = document.getElementById('distSlider');
    const chargeLeft = document.getElementById('chargeLeft');
    const chargeRight = document.getElementById('chargeRight');
    const statusText = document.getElementById('statusText');
    const statusDot = document.getElementById('statusDot');
    const arrowLeft = document.getElementById('forceArrowLeft');
    const arrowRight = document.getElementById('forceArrowRight');
    const headLeft = document.getElementById('headLeft');
    const headRight = document.getElementById('headRight');
    const svgCanvas = document.getElementById('svgCanvas');
    const tabs = document.querySelectorAll('.tab-btn');

    function setMode(mode) {
      currentMode = mode;
      tabs.forEach((tab, i) => {
        tab.classList.toggle('active', 
          (i === 0 && mode === 'opposite') ||
          (i === 1 && mode === 'pos-pos') ||
          (i === 2 && mode === 'neg-neg')
        );
      });
      render();
    }

    function render() {
      const isOpposite = currentMode === 'opposite';
      const isPosPos = currentMode === 'pos-pos';

      // Update Charge Appearances
      if (isOpposite) {
        chargeLeft.className = 'charge charge-pos';
        chargeLeft.innerHTML = '+';
        chargeRight.className = 'charge charge-neg';
        chargeRight.innerHTML = '&minus;';
      } else if (isPosPos) {
        chargeLeft.className = 'charge charge-pos';
        chargeLeft.innerHTML = '+';
        chargeRight.className = 'charge charge-pos';
        chargeRight.innerHTML = '+';
      } else {
        chargeLeft.className = 'charge charge-neg';
        chargeLeft.innerHTML = '&minus;';
        chargeRight.className = 'charge charge-neg';
        chargeRight.innerHTML = '&minus;';
      }

      // Update Status Badge
      statusText.textContent = isOpposite ? 'Attraction (Pull)' : 'Repulsion (Push)';
      statusDot.className = 'dot-indicator' + (isOpposite ? '' : ' repel');

      // Update Force Vector Arrows
      arrowLeft.className = 'force-arrow' + (isOpposite ? '' : ' repel');
      arrowRight.className = 'force-arrow' + (isOpposite ? '' : ' repel');

      if (isOpposite) {
        headLeft.className = 'arrow-head arrow-head-right';
        headRight.className = 'arrow-head arrow-head-left';
      } else {
        headLeft.className = 'arrow-head arrow-head-left';
        headRight.className = 'arrow-head arrow-head-right';
      }

      updatePositions();
    }

    function updatePositions() {
      const d = parseFloat(slider.value);
      const isOpposite = currentMode === 'opposite';
      
      // Calculate force strength (inverse square representation)
      const forceScale = Math.pow(150 / d, 2);
      const arrowLength = Math.min(48, Math.max(14, 18 * forceScale));

      // Dynamic positions
      chargeLeft.style.transform = `translateX(-${d}px)`;
      chargeRight.style.transform = `translateX(${d}px)`;

      arrowLeft.style.width = `${arrowLength}px`;
      arrowRight.style.width = `${arrowLength}px`;

      drawFieldLines(d, isOpposite);
    }

    function drawFieldLines(d, isOpposite) {
      const w = svgCanvas.clientWidth || 380;
      const h = svgCanvas.clientHeight || 220;
      const cx = w / 2;
      const cy = h / 2;
      const x1 = cx - d;
      const x2 = cx + d;

      let html = '';
      if (isOpposite) {
        // Curved attractive field lines connecting charges
        const offsets = [-45, -25, 0, 25, 45];
        offsets.forEach(offset => {
          if (offset === 0) {
            html += `<line x1="${x1 + 32}" y1="${cy}" x2="${x2 - 32}" y2="${cy}" stroke="#10b981" stroke-width="1.5" stroke-dasharray="4,4" opacity="0.6"/>`;
          } else {
            const ctrlY = cy + offset * 1.8;
            html += `<path d="M ${x1 + 20} ${cy + offset*0.4} Q ${cx} ${ctrlY} ${x2 - 20} ${cy + offset*0.4}" fill="none" stroke="#10b981" stroke-width="1.5" stroke-dasharray="4,4" opacity="0.45"/>`;
          }
        });
      } else {
        // Repulsive field lines bending away at the center plane
        const offsets = [-45, -25, 25, 45];
        offsets.forEach(offset => {
          const bendLeftX = cx - (d * 0.35);
          const bendRightX = cx + (d * 0.35);
          html += `<path d="M ${x1 + 24} ${cy + offset*0.3} Q ${bendLeftX} ${cy + offset*0.5} ${bendLeftX} ${cy + offset*1.8}" fill="none" stroke="#f59e0b" stroke-width="1.5" stroke-dasharray="4,4" opacity="0.45"/>`;
          html += `<path d="M ${x2 - 24} ${cy + offset*0.3} Q ${bendRightX} ${cy + offset*0.5} ${bendRightX} ${cy + offset*1.8}" fill="none" stroke="#f59e0b" stroke-width="1.5" stroke-dasharray="4,4" opacity="0.45"/>`;
        });
      }
      svgCanvas.innerHTML = html;
    }

    window.addEventListener('resize', () => updatePositions());
    render();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      height: 100%;
      min-height: 420px;
      padding: 12px 16px;
      user-select: none;
    }

    /* Stepper UI */
    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 8px;
      z-index: 10;
    }
    .step-btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      transition: all 0.25s ease;
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    .step-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.3);
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    .play-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 50%;
      width: 32px;
      height: 32px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 13px;
      cursor: pointer;
      color: #1e2945;
      margin-left: 4px;
    }

    /* Diagram Stage */
    .stage {
      position: relative;
      width: 100%;
      max-width: 580px;
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .view {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.4s ease, transform 0.4s ease;
      transform: scale(0.96);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .view.active {
      opacity: 1;
      pointer-events: auto;
      transform: scale(1);
    }

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

    /* Transfer Electron Animation */
    @keyframes transferMotion {
      0%, 15% { transform: translate(0, 0); opacity: 1; }
      60%, 85% { transform: translate(168px, -24px); opacity: 1; }
      90%, 100% { transform: translate(168px, -24px); opacity: 0; }
    }
    .moving-electron {
      animation: transferMotion 3.2s infinite ease-in-out;
    }

    /* Pulse for lattice attractions */
    @keyframes pulseForce {
      0%, 100% { stroke-opacity: 0.35; stroke-dashoffset: 0; }
      50% { stroke-opacity: 0.9; stroke-dashoffset: 6; }
    }
    .force-line {
      stroke: #f59e0b;
      stroke-width: 2.5;
      stroke-dasharray: 4 3;
      animation: pulseForce 2s infinite ease-in-out;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="step-btn active" onclick="setStep(0)">1. Transfer</button>
    <button class="step-btn" onclick="setStep(1)">2. Ions</button>
    <button class="step-btn" onclick="setStep(2)">3. Giant Lattice</button>
    <button class="play-btn" id="playBtn" onclick="togglePlay()" title="Play/Pause">⏸</button>
  </div>

  
  <div class="stage">
    
    
    <div class="view active" id="view-0">
      <svg viewBox="0 0 520 300">
        
        <path d="M 205 130 Q 260 70 315 125" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="5 4" marker-end="url(#arrowhead)" />
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          <marker id="arrowhead" markerWidth="8" markerHeight="6" refX="6" refY="3" orient="auto">
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        <g transform="translate(130, 150)">
          <circle cx="0" cy="0" r="18" fill="#e0f2fe" stroke="#0284c7" stroke-width="2" />
          <text x="0" y="5" text-anchor="middle" font-size="14" font-weight="bold" fill="#0369a1">Na</text>
          
          
          <circle cx="0" cy="0" r="38" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="58" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="78" fill="none" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3 3" />

          
          <circle cx="0" cy="-38" r="4" fill="#0284c7" />
          <circle cx="0" cy="38" r="4" fill="#0284c7" />
          
          
          <circle cx="-58" cy="0" r="4" fill="#0284c7" />
          <circle cx="58" cy="0" r="4" fill="#0284c7" />
          <circle cx="-41" cy="-41" r="4" fill="#0284c7" />
          <circle cx="41" cy="-41" r="4" fill="#0284c7" />
          <circle cx="-41" cy="41" r="4" fill="#0284c7" />
          <circle cx="41" cy="41" r="4" fill="#0284c7" />
          <circle cx="0" cy="-58" r="4" fill="#0284c7" />
          <circle cx="0" cy="58" r="4" fill="#0284c7" />

          
          <g class="moving-electron">
            <circle cx="78" cy="0" r="5" fill="#f59e0b" stroke="#b45309" stroke-width="1" />
          </g>

          <text x="0" y="105" text-anchor="middle" font-size="13" font-weight="600" fill="#475569">Na (2,8,1)</text>
        </g>

        
        <g transform="translate(390, 150)">
          <circle cx="0" cy="0" r="18" fill="#dcfce7" stroke="#16a34a" stroke-width="2" />
          <text x="0" y="5" text-anchor="middle" font-size="14" font-weight="bold" fill="#15803d">Cl</text>

          
          <circle cx="0" cy="0" r="38" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="58" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="78" fill="none" stroke="#cbd5e1" stroke-width="1.5" />

          
          <circle cx="0" cy="-38" r="4" fill="#16a34a" />
          <circle cx="0" cy="38" r="4" fill="#16a34a" />

          
          <circle cx="-58" cy="0" r="4" fill="#16a34a" />
          <circle cx="58" cy="0" r="4" fill="#16a34a" />
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          <circle cx="-41" cy="41" r="4" fill="#16a34a" />
          <circle cx="41" cy="41" r="4" fill="#16a34a" />
          <circle cx="0" cy="-58" r="4" fill="#16a34a" />
          <circle cx="0" cy="58" r="4" fill="#16a34a" />

          
          <circle cx="0" cy="-78" r="4" fill="#16a34a" />
          <circle cx="0" cy="78" r="4" fill="#16a34a" />
          <circle cx="78" cy="0" r="4" fill="#16a34a" />
          <circle cx="-55" cy="-55" r="4" fill="#16a34a" />
          <circle cx="55" cy="-55" r="4" fill="#16a34a" />
          <circle cx="-55" cy="55" r="4" fill="#16a34a" />
          <circle cx="55" cy="55" r="4" fill="#16a34a" />

          
          <circle cx="-78" cy="0" r="5" fill="none" stroke="#f59e0b" stroke-width="1.5" stroke-dasharray="2 2" />

          <text x="0" y="105" text-anchor="middle" font-size="13" font-weight="600" fill="#475569">Cl (2,8,7)</text>
        </g>
      </svg>
    </div>

    
    <div class="view" id="view-1">
      <svg viewBox="0 0 520 300">
        
        <g transform="translate(260, 145)">
          <path d="M -30 0 L 30 0" stroke="#f59e0b" stroke-width="3" stroke-dasharray="4 3" />
          <text x="0" y="-12" text-anchor="middle" font-size="12" font-weight="bold" fill="#d97706">Attraction</text>
        </g>

        
        <g transform="translate(130, 145)">
          
          <path d="M -75 -75 L -85 -75 L -85 75 L -75 75" fill="none" stroke="#1e2945" stroke-width="2.5" />
          <path d="M 75 -75 L 85 -75 L 85 75 L 75 75" fill="none" stroke="#1e2945" stroke-width="2.5" />
          <text x="96" y="-62" font-size="24" font-weight="bold" fill="#0284c7">+</text>

          <circle cx="0" cy="0" r="18" fill="#e0f2fe" stroke="#0284c7" stroke-width="2" />
          <text x="0" y="5" text-anchor="middle" font-size="14" font-weight="bold" fill="#0369a1">Na</text>

          <circle cx="0" cy="0" r="38" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="60" fill="none" stroke="#cbd5e1" stroke-width="1.5" />

          
          <circle cx="0" cy="-38" r="4" fill="#0284c7" />
          <circle cx="0" cy="38" r="4" fill="#0284c7" />
          
          
          <circle cx="-60" cy="0" r="4" fill="#0284c7" />
          <circle cx="60" cy="0" r="4" fill="#0284c7" />
          <circle cx="-42" cy="-42" r="4" fill="#0284c7" />
          <circle cx="42" cy="-42" r="4" fill="#0284c7" />
          <circle cx="-42" cy="42" r="4" fill="#0284c7" />
          <circle cx="42" cy="42" r="4" fill="#0284c7" />
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          <circle cx="0" cy="60" r="4" fill="#0284c7" />

          <text x="0" y="105" text-anchor="middle" font-size="13" font-weight="600" fill="#475569">[Na]⁺ (2,8)</text>
        </g>

        
        <g transform="translate(390, 145)">
          
          <path d="M -90 -90 L -100 -90 L -100 90 L -90 90" fill="none" stroke="#1e2945" stroke-width="2.5" />
          <path d="M 90 -90 L 100 -90 L 100 90 L 90 90" fill="none" stroke="#1e2945" stroke-width="2.5" />
          <text x="110" y="-76" font-size="28" font-weight="bold" fill="#16a34a">−</text>

          <circle cx="0" cy="0" r="18" fill="#dcfce7" stroke="#16a34a" stroke-width="2" />
          <text x="0" y="5" text-anchor="middle" font-size="14" font-weight="bold" fill="#15803d">Cl</text>

          <circle cx="0" cy="0" r="38" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="58" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
          <circle cx="0" cy="0" r="78" fill="none" stroke="#cbd5e1" stroke-width="1.5" />

          
          <circle cx="0" cy="-38" r="4" fill="#16a34a" />
          <circle cx="0" cy="38" r="4" fill="#16a34a" />

          
          <circle cx="-58" cy="0" r="4" fill="#16a34a" />
          <circle cx="58" cy="0" r="4" fill="#16a34a" />
          <circle cx="-41" cy="-41" r="4" fill="#16a34a" />
          <circle cx="41" cy="-41" r="4" fill="#16a34a" />
          <circle cx="-41" cy="41" r="4" fill="#16a34a" />
          <circle cx="41" cy="41" r="4" fill="#16a34a" />
          <circle cx="0" cy="-58" r="4" fill="#16a34a" />
          <circle cx="0" cy="58" r="4" fill="#16a34a" />

          
          <circle cx="0" cy="-78" r="4" fill="#16a34a" />
          <circle cx="0" cy="78" r="4" fill="#16a34a" />
          <circle cx="78" cy="0" r="4" fill="#16a34a" />
          <circle cx="-55" cy="-55" r="4" fill="#16a34a" />
          <circle cx="55" cy="-55" r="4" fill="#16a34a" />
          <circle cx="-55" cy="55" r="4" fill="#16a34a" />
          <circle cx="55" cy="55" r="4" fill="#16a34a" />
          
          <circle cx="-78" cy="0" r="4.5" fill="#f59e0b" stroke="#b45309" stroke-width="1" />

          <text x="0" y="112" text-anchor="middle" font-size="13" font-weight="600" fill="#475569">[Cl]⁻ (2,8,8)</text>
        </g>
      </svg>
    </div>

    
    <div class="view" id="view-2">
      <svg viewBox="0 0 520 300">
        
        <g transform="translate(260, 25)">
          <rect x="-135" y="-14" width="270" height="28" rx="14" fill="#fef3c7" stroke="#f59e0b" stroke-width="1.5" />
          <text x="0" y="5" text-anchor="middle" font-size="12" font-weight="bold" fill="#b45309">
            Electrostatic forces in all directions
          </text>
        </g>

        
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          <line x1="80" y1="-80" x2="80" y2="0" class="force-line" />

          
          <line x1="-80" y1="-80" x2="-40" y2="-40" class="force-line" />
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          <line x1="-80" y1="0" x2="-40" y2="40" class="force-line" />
          <line x1="0" y1="0" x2="40" y2="40" class="force-line" />
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          <line x1="-40" y1="-40" x2="40" y2="-40" class="force-line" />
          <line x1="40" y1="-40" x2="120" y2="-40" class="force-line" />
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          <line x1="120" y1="-40" x2="120" y2="40" class="force-line" />

          
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            <line x1="-40" y1="40" x2="-70" y2="60" stroke-dasharray="2 2" />
            <line x1="120" y1="-40" x2="150" y2="-60" stroke-dasharray="2 2" />
          </g>

          
          
          <circle cx="-80" cy="-80" r="10" fill="#0284c7" opacity="0.7" />
          
          <circle cx="0" cy="-80" r="15" fill="#16a34a" opacity="0.7" />
          
          <circle cx="80" cy="-80" r="10" fill="#0284c7" opacity="0.7" />
          
          <circle cx="-80" cy="0" r="15" fill="#16a34a" opacity="0.7" />
          
          <circle cx="0" cy="0" r="10" fill="#0284c7" opacity="0.7" />
          
          <circle cx="80" cy="0" r="15" fill="#16a34a" opacity="0.7" />

          
          
          <circle cx="-40" cy="-40" r="18" fill="#22c55e" stroke="#15803d" stroke-width="2" />
          <text x="-40" y="-35" text-anchor="middle" font-size="11" font-weight="bold" fill="#ffffff">Cl⁻</text>

          
          <circle cx="40" cy="-40" r="13" fill="#38bdf8" stroke="#0284c7" stroke-width="2" />
          <text x="40" y="-36" text-anchor="middle" font-size="10" font-weight="bold" fill="#ffffff">Na⁺</text>

          
          <circle cx="120" cy="-40" r="18" fill="#22c55e" stroke="#15803d" stroke-width="2" />
          <text x="120" y="-35" text-anchor="middle" font-size="11" font-weight="bold" fill="#ffffff">Cl⁻</text>

          
          <circle cx="-40" cy="40" r="13" fill="#38bdf8" stroke="#0284c7" stroke-width="2" />
          <text x="-40" y="44" text-anchor="middle" font-size="10" font-weight="bold" fill="#ffffff">Na⁺</text>

          
          <circle cx="40" cy="40" r="18" fill="#22c55e" stroke="#15803d" stroke-width="2" />
          <text x="40" y="45" text-anchor="middle" font-size="11" font-weight="bold" fill="#ffffff">Cl⁻</text>

          
          <circle cx="120" cy="40" r="13" fill="#38bdf8" stroke="#0284c7" stroke-width="2" />
          <text x="120" y="44" text-anchor="middle" font-size="10" font-weight="bold" fill="#ffffff">Na⁺</text>
        </g>
      </svg>
    </div>

  </div>

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

    const views = [
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      playBtn.textContent = isPlaying ? '⏸' : '▶';
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    // Auto-advance loop
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  </script>
</body>
</html>

UK-GCSE-SCIENCE-CHEM-SBM-02-02

Aligned learning resources

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