<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      background: #f1f5f9;
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
    }
    .diagram-wrap {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .controls {
      display: flex;
      justify-content: center;
      gap: 6px;
    }
    .step-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 4px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      box-shadow: 0 1px 2px rgba(0,0,0,0.05);
      transition: all 0.25s ease;
    }
    .step-btn.active {
      background: #1e293b;
      color: #ffffff;
      border-color: #1e293b;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      border-radius: 12px;
      box-shadow: 0 4px 12px rgba(0,0,0,0.08);
      background: #1e293b;
    }
    .summary-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
      width: 100%;
    }
    .summary-card {
      background: #ffffff;
      border-radius: 8px;
      padding: 8px 12px;
      display: flex;
      flex-direction: column;
      border-left: 4px solid #cbd5e1;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    }
    .summary-card.predation {
      border-left-color: #e11d48;
    }
    .summary-card.camouflage {
      border-left-color: #22c55e;
    }
    .summary-label {
      font-size: 11px;
      text-transform: uppercase;
      font-weight: 700;
      color: #64748b;
      letter-spacing: 0.5px;
    }
    .summary-val {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
    }
    .target-line {
      stroke: #e11d48;
      stroke-width: 1.5;
      stroke-dasharray: 4, 3;
      animation: dash 1s linear infinite;
    }
    @keyframes dash {
      to { stroke-dashoffset: -7; }
    }
    .safe-ring {
      stroke: #22c55e;
      stroke-width: 1.5;
      stroke-dasharray: 2, 2;
      fill: none;
      opacity: 0.85;
    }
  </style>
</head>
<body>
  <div class="diagram-wrap">
    <div class="controls">
      <button class="step-btn active" id="btn1" onclick="setMode('hunt')">Predator Hunt</button>
      <button class="step-btn" id="btn2" onclick="setMode('vision')">Visibility Contrast</button>
    </div>

    <svg viewBox="0 0 600 360" aria-label="Beetle Natural Selection Diagram">
      <defs>
        
        <radialGradient id="rockShub" cx="50%" cy="50%" r="50%">
          <stop offset="0%" stop-color="#334155" />
          <stop offset="100%" stop-color="#1e293b" />
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          <path d="M 0 1 L 10 5 L 0 9 z" fill="#e11d48" />
        </marker>
        
        <g id="beetle-body">
          <line x1="-3" y1="-8" x2="-8" y2="-14" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="3" y1="-8" x2="8" y2="-14" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          
          <line x1="-6" y1="-4" x2="-13" y2="-6" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="6" y1="-4" x2="13" y2="-6" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="-7" y1="0" x2="-14" y2="1" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="7" y1="0" x2="14" y2="1" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="-6" y1="5" x2="-12" y2="9" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          <line x1="6" y1="5" x2="12" y2="9" stroke="currentColor" stroke-width="1.2" stroke-linecap="round"/>
          
          <circle cx="0" cy="-7" r="3.5" fill="currentColor"/>
          <ellipse cx="0" cy="-3" rx="5.5" ry="3.5" fill="currentColor"/>
          
          <ellipse cx="0" cy="5" rx="7.5" ry="9.5" fill="currentColor"/>
          <line x1="0" y1="-2" x2="0" y2="14" stroke="#0f172a" stroke-width="0.8" opacity="0.6"/>
        </g>
      </defs>

      
      <rect width="600" height="360" fill="#1e293b"/>
      <rect width="600" height="120" fill="url(#skyGrad)"/>

      
      <path d="M 20 160 Q 90 130 180 150 T 320 170 T 450 140 T 580 165 L 600 360 L 0 360 Z" fill="#0f172a" opacity="0.6"/>
      <path d="M 0 220 Q 110 190 230 210 T 470 200 T 600 230 L 600 360 L 0 360 Z" fill="#182234"/>
      
      
      <ellipse cx="140" cy="260" rx="45" ry="18" fill="#0f172a" opacity="0.8"/>
      <ellipse cx="370" cy="300" rx="70" ry="24" fill="#0f172a" opacity="0.7"/>
      <ellipse cx="500" cy="220" rx="35" ry="14" fill="#0f172a" opacity="0.9"/>
      <ellipse cx="280" cy="210" rx="50" ry="16" fill="#0f172a" opacity="0.5"/>
      <ellipse cx="70" cy="320" rx="55" ry="20" fill="#0f172a" opacity="0.7"/>

      
      <g transform="translate(300, 48) scale(0.95)" fill="#0f172a">
        
        <path d="M 0 -12 C 15 -18 45 -22 90 -16 C 125 -10 150 2 170 18 C 145 16 120 12 95 18 C 70 24 50 36 30 52 C 18 40 10 38 0 42 C -10 38 -18 40 -30 52 C -50 36 -70 24 -95 18 C -120 12 -145 16 -170 18 C -150 2 -125 -10 -90 -16 C -45 -22 -15 -18 0 -12 Z" />
        
        <polygon points="0,-12 -5,-4 0,4 5,-4" fill="#020617"/>
        <polygon points="0,-12 -2,-8 0,-18 2,-8" fill="#e11d48"/>
      </g>
      <text x="300" y="22" fill="#94a3b8" font-size="12" font-weight="700" text-anchor="middle" letter-spacing="1">PREDATOR (BIRD)</text>

      
      <g id="huntGroup">
        
        <line x1="285" y1="75" x2="80" y2="185" class="target-line" marker-end="url(#arrow)"/>
        <line x1="295" y1="78" x2="210" y2="245" class="target-line" marker-end="url(#arrow)"/>
        <line x1="300" y1="80" x2="330" y2="180" class="target-line" marker-end="url(#arrow)"/>
        <line x1="305" y1="78" x2="430" y2="265" class="target-line" marker-end="url(#arrow)"/>
        <line x1="315" y1="75" x2="520" y2="195" class="target-line" marker-end="url(#arrow)"/>
      </g>

      
      
      <g transform="translate(130, 215) rotate(25)" style="color: #382419;">
        <use href="#beetle-body"/>
      </g>
      
      <g transform="translate(260, 290) rotate(-40)" style="color: #312015;">
        <use href="#beetle-body"/>
      </g>
      
      <g transform="translate(385, 225) rotate(15)" style="color: #382419;">
        <use href="#beetle-body"/>
      </g>
      
      <g transform="translate(485, 305) rotate(-10)" style="color: #2b1a10;">
        <use href="#beetle-body"/>
      </g>
      
      <g transform="translate(60, 295) rotate(50)" style="color: #332117;">
        <use href="#beetle-body"/>
      </g>

      
      
      <g id="y1" transform="translate(80, 195) rotate(-15)" style="color: #facc15;">
        <circle cx="0" cy="3" r="14" fill="#fef08a" opacity="0.25"/>
        <use href="#beetle-body"/>
      </g>
      
      <g id="y2" transform="translate(210, 255) rotate(35)" style="color: #facc15;">
        <circle cx="0" cy="3" r="14" fill="#fef08a" opacity="0.25"/>
        <use href="#beetle-body"/>
      </g>
      
      <g id="y3" transform="translate(330, 190) rotate(-20)" style="color: #facc15;">
        <circle cx="0" cy="3" r="14" fill="#fef08a" opacity="0.25"/>
        <use href="#beetle-body"/>
      </g>
      
      <g id="y4" transform="translate(430, 275) rotate(45)" style="color: #facc15;">
        <circle cx="0" cy="3" r="14" fill="#fef08a" opacity="0.25"/>
        <use href="#beetle-body"/>
      </g>
      
      <g id="y5" transform="translate(520, 205) rotate(-30)" style="color: #facc15;">
        <circle cx="0" cy="3" r="14" fill="#fef08a" opacity="0.25"/>
        <use href="#beetle-body"/>
      </g>

      
      <g id="visionGroup" style="display: none;">
        
        <circle cx="80" cy="195" r="16" stroke="#e11d48" stroke-width="2" fill="none"/>
        <circle cx="210" cy="255" r="16" stroke="#e11d48" stroke-width="2" fill="none"/>
        <circle cx="330" cy="190" r="16" stroke="#e11d48" stroke-width="2" fill="none"/>
        <circle cx="430" cy="275" r="16" stroke="#e11d48" stroke-width="2" fill="none"/>
        <circle cx="520" cy="205" r="16" stroke="#e11d48" stroke-width="2" fill="none"/>

        
        <circle cx="130" cy="215" r="16" class="safe-ring"/>
        <circle cx="260" cy="290" r="16" class="safe-ring"/>
        <circle cx="385" cy="225" r="16" class="safe-ring"/>
        <circle cx="485" cy="305" r="16" class="safe-ring"/>
        <circle cx="60" cy="295" r="16" class="safe-ring"/>
      </g>

      
      <g transform="translate(20, 335)">
        <circle cx="8" cy="0" r="5" fill="#facc15"/>
        <text x="18" y="4" fill="#facc15" font-size="11" font-weight="700">Bright Yellow (Visible)</text>
      </g>
      <g transform="translate(420, 335)">
        <circle cx="8" cy="0" r="5" fill="#543729" stroke="#94a3b8" stroke-width="0.8"/>
        <text x="18" y="4" fill="#94a3b8" font-size="11" font-weight="700">Dark Brown (Camouflaged)</text>
      </g>
    </svg>

    
    <div class="summary-grid">
      <div class="summary-card predation">
        <span class="summary-label">Selection Pressure</span>
        <span class="summary-val">Predation</span>
      </div>
      <div class="summary-card camouflage">
        <span class="summary-label">Key Factor</span>
        <span class="summary-val">Camouflage</span>
      </div>
    </div>
  </div>

  <script>
    function setMode(mode) {
      const huntGroup = document.getElementById('huntGroup');
      const visionGroup = document.getElementById('visionGroup');
      const btn1 = document.getElementById('btn1');
      const btn2 = document.getElementById('btn2');

      if (mode === 'hunt') {
        huntGroup.style.display = 'block';
        visionGroup.style.display = 'none';
        btn1.classList.add('active');
        btn2.classList.remove('active');
      } else {
        huntGroup.style.display = 'none';
        visionGroup.style.display = 'block';
        btn2.classList.add('active');
        btn1.classList.remove('active');
      }
    }
  </script>
</body>
</html>

Darwin's Theory of Evolution by Natural Selection

<!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>Allele Frequency Shift</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    }

    body {
      padding: 16px;
      color: #1e2945;
      background: transparent;
      display: flex;
      flex-direction: column;
      gap: 12px;
      justify-content: center;
      min-height: 100%;
    }

    .legend {
      display: flex;
      justify-content: center;
      gap: 18px;
      font-size: 14px;
      font-weight: 600;
    }

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

    .swatch {
      width: 14px;
      height: 14px;
      border-radius: 4px;
    }

    .swatch-dark {
      background: #0284c7;
    }

    .swatch-light {
      background: #cbd5e1;
      border: 1px solid #94a3b8;
    }

    .generations {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .gen-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      display: flex;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      transition: box-shadow 0.2s ease, background 0.2s ease;
    }

    .gen-card.active {
      background: #ffffff;
      box-shadow: 0 0 0 2px #0284c7, 0 4px 12px rgba(2, 132, 199, 0.08);
    }

    .gen-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 14px;
      font-weight: 700;
    }

    .gen-title {
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .badge {
      background: #e2e8f0;
      color: #1e2945;
      font-size: 12px;
      padding: 2px 7px;
      border-radius: 999px;
      font-weight: 600;
    }

    .gen-stats {
      font-size: 13px;
      font-weight: 600;
      color: #475569;
    }

    .bar-track {
      width: 100%;
      height: 24px;
      background: #cbd5e1;
      border-radius: 6px;
      overflow: hidden;
      display: flex;
      position: relative;
    }

    .bar-segment-b {
      background: #0284c7;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #ffffff;
      font-size: 12px;
      font-weight: 700;
      transition: width 0.5s ease;
    }

    .bar-segment-light {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #334155;
      font-size: 12px;
      font-weight: 700;
    }

    .annotation-box {
      display: flex;
      align-items: center;
      gap: 8px;
      background: #f0f9ff;
      border-left: 3px solid #0284c7;
      border-radius: 0 8px 8px 0;
      padding: 8px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #0369a1;
      line-height: 1.35;
    }

    .arrow-icon {
      font-size: 16px;
      flex-shrink: 0;
    }

    .controls {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-top: 2px;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      padding: 6px 14px;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background 0.15s ease, box-shadow 0.15s ease;
    }

    .btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }
  </style>
</head>
<body>

  
  <div class="legend">
    <div class="legend-item">
      <span class="swatch swatch-dark"></span>
      <span>Dark fur allele (B)</span>
    </div>
    <div class="legend-item">
      <span class="swatch swatch-light"></span>
      <span>Light fur allele (b)</span>
    </div>
  </div>

  
  <div class="generations">
    
    <div class="gen-card active" id="card-1" onclick="selectGen(0)">
      <div class="gen-header">
        <span class="gen-title">Generation 1 <span class="badge">Initial</span></span>
        <span class="gen-stats">20% B · 80% b</span>
      </div>
      <div class="bar-track">
        <div class="bar-segment-b" style="width: 20%;">20%</div>
        <div class="bar-segment-light">80%</div>
      </div>
    </div>

    
    <div class="gen-card" id="card-2" onclick="selectGen(1)">
      <div class="gen-header">
        <span class="gen-title">Generation 2 <span class="badge">Selection</span></span>
        <span class="gen-stats">50% B · 50% b</span>
      </div>
      <div class="bar-track">
        <div class="bar-segment-b" style="width: 50%;">50%</div>
        <div class="bar-segment-light">50%</div>
      </div>
    </div>

    
    <div class="gen-card" id="card-3" onclick="selectGen(2)">
      <div class="gen-header">
        <span class="gen-title">Generation 3 <span class="badge">Adapted</span></span>
        <span class="gen-stats">85% B · 15% b</span>
      </div>
      <div class="bar-track">
        <div class="bar-segment-b" style="width: 85%;">85%</div>
        <div class="bar-segment-light">15%</div>
      </div>
    </div>
  </div>

  
  <div class="annotation-box">
    <span class="arrow-icon">↓</span>
    <span>Allele frequency shifts across generations — the population evolves, not individual organisms.</span>
  </div>

  
  <div class="controls">
    <button class="btn active" id="btn-0" onclick="selectGen(0)">Gen 1</button>
    <button class="btn" id="btn-1" onclick="selectGen(1)">Gen 2</button>
    <button class="btn" id="btn-2" onclick="selectGen(2)">Gen 3</button>
    <button class="btn" id="btn-all" onclick="selectAll()">Show All</button>
  </div>

  <script>
    let currentIdx = 0;
    const cards = [document.getElementById('card-1'), document.getElementById('card-2'), document.getElementById('card-3')];
    const btns = [document.getElementById('btn-0'), document.getElementById('btn-1'), document.getElementById('btn-2'), document.getElementById('btn-all')];

    function selectGen(idx) {
      currentIdx = idx;
      cards.forEach((c, i) => {
        if (i === idx) {
          c.classList.add('active');
          c.style.opacity = '1';
        } else {
          c.classList.remove('active');
          c.style.opacity = '0.55';
        }
      });
      btns.forEach((b, i) => {
        b.classList.toggle('active', i === idx);
      });
    }

    function selectAll() {
      cards.forEach(c => {
        c.classList.add('active');
        c.style.opacity = '1';
      });
      btns.forEach((b, i) => {
        b.classList.toggle('active', i === 3);
      });
    }

    // Initialize showing all generations for direct visual comparison
    selectAll();
  </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="4:5">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background-color: #f8fafc;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 10px 8px;
      user-select: none;
      -webkit-user-select: none;
    }
    .flow-container {
      width: 100%;
      max-width: 360px;
      display: flex;
      flex-direction: column;
      gap: 5px;
    }
    .header-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 4px 4px 4px;
    }
    .stepper-dots {
      display: flex;
      gap: 6px;
      align-items: center;
    }
    .dot-btn {
      width: 24px;
      height: 24px;
      border-radius: 50%;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      color: #64748b;
      font-size: 11px;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s ease;
    }
    .dot-btn.active {
      background: #0d9488;
      border-color: #0d9488;
      color: #ffffff;
      box-shadow: 0 0 0 2px rgba(13, 148, 136, 0.25);
    }
    .play-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      color: #0d9488;
      font-size: 11px;
      font-weight: 600;
      padding: 4px 8px;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s ease;
    }
    .play-btn:active {
      background: #f1f5f9;
    }
    .step-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 8px;
      padding: 7px 10px;
      display: grid;
      grid-template-columns: 20px 1fr auto;
      align-items: center;
      gap: 8px;
      cursor: pointer;
      transition: border-color 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
    }
    .step-card:hover {
      background: #f0fdfa;
    }
    .step-card.active {
      border-color: #0d9488;
      background: #f0fdfa;
      box-shadow: 0 0 0 2px rgba(13, 148, 136, 0.2);
    }
    .step-num {
      width: 20px;
      height: 20px;
      border-radius: 50%;
      background: #e2e8f0;
      color: #1e2945;
      font-size: 11px;
      font-weight: 800;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s ease;
    }
    .step-card.active .step-num {
      background: #0d9488;
      color: #ffffff;
    }
    .step-title {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      letter-spacing: -0.01em;
    }
    .visual-stage {
      display: flex;
      align-items: center;
      gap: 4px;
      background: #f8fafc;
      padding: 3px 6px;
      border-radius: 6px;
      border: 1px solid #edf2f7;
      min-height: 30px;
    }
    .connector {
      display: flex;
      justify-content: center;
      align-items: center;
      height: 12px;
      color: #94a3b8;
      font-size: 10px;
      line-height: 1;
      transition: color 0.25s ease;
    }
    .connector.active {
      color: #0d9488;
    }
    
    /* Semantic item representations */
    .mouse {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 15px;
      line-height: 1;
      border-radius: 4px;
      padding: 1px;
    }
    .mouse.brown {
      filter: sepia(1) saturate(3) hue-rotate(345deg) brightness(0.7);
    }
    .mouse.white {
      filter: grayscale(1) brightness(1.6) contrast(0.9);
      opacity: 0.9;
    }
    .mouse.caught {
      position: relative;
      opacity: 0.45;
      filter: grayscale(1) brightness(1.3);
    }
    .cross-mark {
      color: #dc2626;
      font-size: 11px;
      font-weight: 900;
      margin-left: -6px;
      margin-top: -8px;
    }
    .dna {
      font-size: 13px;
    }
    .food {
      font-size: 13px;
    }
    .hawk {
      font-size: 14px;
    }
    .vs-tag {
      font-size: 9px;
      font-weight: 800;
      color: #94a3b8;
    }
    .ground {
      background: #78350f;
      border-radius: 4px;
      padding: 1px 4px;
      display: inline-flex;
      align-items: center;
      gap: 2px;
    }
    .freq-box {
      font-size: 11px;
      font-weight: 700;
      color: #0d9488;
      margin-left: 2px;
    }
  </style>
</head>
<body>

  <div class="flow-container">
    <div class="header-bar">
      <div class="stepper-dots">
        <button class="dot-btn active" onclick="setStep(0)">1</button>
        <button class="dot-btn" onclick="setStep(1)">2</button>
        <button class="dot-btn" onclick="setStep(2)">3</button>
        <button class="dot-btn" onclick="setStep(3)">4</button>
        <button class="dot-btn" onclick="setStep(4)">5</button>
      </div>
      <button class="play-btn" id="playBtn" onclick="togglePlay()">
        <span id="playIcon">⏸</span> Auto
      </button>
    </div>

    
    <div class="step-card active" onclick="setStep(0)" id="card-0">
      <div class="step-num">1</div>
      <div class="step-title">Genetic Variation</div>
      <div class="visual-stage">
        <span class="dna">🧬</span>
        <span class="mouse brown">🐭</span>
        <span class="vs-tag">/</span>
        <span class="mouse white">🐭</span>
      </div>
    </div>

    <div class="connector active" id="conn-0">▼</div>

    
    <div class="step-card" onclick="setStep(1)" id="card-1">
      <div class="step-num">2</div>
      <div class="step-title">Overproduction</div>
      <div class="visual-stage">
        <span class="mouse brown">🐭</span>
        <span class="mouse white">🐭</span>
        <span class="mouse brown">🐭</span>
        <span class="mouse white">🐭</span>
        <span class="mouse brown">🐭</span>
      </div>
    </div>

    <div class="connector" id="conn-1">▼</div>

    
    <div class="step-card" onclick="setStep(2)" id="card-2">
      <div class="step-num">3</div>
      <div class="step-title">Competition</div>
      <div class="visual-stage">
        <span class="food">🌾</span>
        <span class="hawk">🦅</span>
        <span class="mouse brown">🐭</span>
        <span class="mouse white">🐭</span>
      </div>
    </div>

    <div class="connector" id="conn-2">▼</div>

    
    <div class="step-card" onclick="setStep(3)" id="card-3">
      <div class="step-num">4</div>
      <div class="step-title">Survival</div>
      <div class="visual-stage">
        <div class="ground">
          <span class="mouse brown">🐭</span>
        </div>
        <span class="mouse caught">🐭</span>
        <span class="cross-mark">✕</span>
      </div>
    </div>

    <div class="connector" id="conn-3">▼</div>

    
    <div class="step-card" onclick="setStep(4)" id="card-4">
      <div class="step-num">5</div>
      <div class="step-title">Evolution</div>
      <div class="visual-stage">
        <span class="mouse brown">🐭</span>
        <span class="mouse brown">🐭</span>
        <span class="mouse brown">🐭</span>
        <span class="freq-box">↑ 100%</span>
      </div>
    </div>
  </div>

  <script>
    let currentStep = 0;
    let isPlaying = true;
    let timer = null;
    const totalSteps = 5;

    function render() {
      for (let i = 0; i < totalSteps; i++) {
        const card = document.getElementById('card-' + i);
        const dots = document.querySelectorAll('.dot-btn');
        const conn = document.getElementById('conn-' + i);

        if (i === currentStep) {
          card.classList.add('active');
          if (dots[i]) dots[i].classList.add('active');
          if (conn) conn.classList.add('active');
        } else {
          card.classList.remove('active');
          if (dots[i]) dots[i].classList.remove('active');
          if (conn) conn.classList.remove('active');
        }
      }
    }

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

    function nextStep() {
      currentStep = (currentStep + 1) % totalSteps;
      render();
    }

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

    function startTimer() {
      clearInterval(timer);
      timer = setInterval(nextStep, 3000);
    }

    // Initialize
    render();
    startTimer();
  </script>
</body>
</html>

UK-GCSE-SCIENCE-BIO-IVE-03-04

Aligned learning resources

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