<!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" />
        </radialGradient>
        <linearGradient id="skyGrad" x1="0" y1="0" x2="0" y2="1">
          <stop offset="0%" stop-color="#64748b" stop-opacity="0.35"/>
          <stop offset="100%" stop-color="#1e293b" stop-opacity="0"/>
        </linearGradient>
        
        <marker id="arrow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <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>

<!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>Preservation Without Decay</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;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      user-select: none;
    }

    .header-tag {
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      color: #6b7280;
      text-align: center;
    }

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

    @media (max-width: 520px) {
      .grid {
        grid-template-columns: 1fr;
      }
    }

    .specimen-card {
      background: #ffffff;
      border: 1.5px solid #e5e7eb;
      border-radius: 12px;
      padding: 14px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      gap: 10px;
      cursor: pointer;
      transition: border-color 0.25s ease, box-shadow 0.25s ease;
    }

    .specimen-card.active {
      border-color: #22b7ff;
      box-shadow: 0 0 0 3px rgba(34, 183, 255, 0.2);
    }

    .badge {
      background: #e0f4ff;
      color: #0077b6;
      border: 1px solid #bae6fd;
      font-size: 11px;
      font-weight: 700;
      padding: 3px 8px;
      border-radius: 999px;
      letter-spacing: 0.02em;
    }

    .view-portal {
      width: 84px;
      height: 84px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      font-size: 38px;
      border: 3px solid rgba(255, 255, 255, 0.8);
      box-shadow: inset 0 2px 6px rgba(0,0,0,0.1), 0 4px 10px rgba(0,0,0,0.06);
    }

    .amber-bg {
      background: radial-gradient(circle at 35% 35%, #ffd166 0%, #f48c06 70%, #d97706 100%);
    }

    .ice-bg {
      background: radial-gradient(circle at 35% 35%, #e0f2fe 0%, #7dd3fc 60%, #0284c7 100%);
    }

    .bog-bg {
      background: radial-gradient(circle at 35% 35%, #a78bfa 0%, #5b21b6 70%, #311042 100%);
    }

    .specimen-title {
      font-size: 14px;
      font-weight: 800;
      color: #0f172a;
    }

    .barrier-pill {
      background: #fef2f2;
      border: 1px solid #fecaca;
      color: #dc2626;
      font-size: 11px;
      font-weight: 700;
      padding: 4px 8px;
      border-radius: 6px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    .status-banner {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 12px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: 12px;
      font-weight: 600;
      color: #334155;
    }

    .decay-tag {
      background: #dcfce7;
      color: #15803d;
      border: 1px solid #bbf7d0;
      padding: 2px 6px;
      border-radius: 4px;
      font-size: 11px;
      font-weight: 700;
    }
  </style>
</head>
<body>

  <div class="header-tag">Conditions for Zero Decay</div>

  <div class="grid">
    
    <div class="specimen-card active" id="card-0" onclick="selectCard(0)">
      <span class="badge">Tree Resin</span>
      <div class="view-portal amber-bg">
        <span>🐜</span>
      </div>
      <div class="specimen-title">Amber</div>
      <div class="barrier-pill">🚫 No O₂ / Moisture</div>
    </div>

    
    <div class="specimen-card" id="card-1" onclick="selectCard(1)">
      <span class="badge">Permafrost</span>
      <div class="view-portal ice-bg">
        <span>🦣</span>
      </div>
      <div class="specimen-title">Glacial Ice</div>
      <div class="barrier-pill">🚫 No Heat (Enzymes Stop)</div>
    </div>

    
    <div class="specimen-card" id="card-2" onclick="selectCard(2)">
      <span class="badge">Acidic Peat</span>
      <div class="view-portal bog-bg">
        <span>👤</span>
      </div>
      <div class="specimen-title">Peat Bog</div>
      <div class="barrier-pill">🚫 Acid Kills Bacteria</div>
    </div>
  </div>

  <div class="status-banner">
    <span id="detail-text">Resin seals out air &amp; water — body intact</span>
    <span class="decay-tag">✓ 0% DECAY</span>
  </div>

  <script>
    const descriptions = [
      "Resin seals out air & water — body intact",
      "Sub-zero cold freezes microbes & enzymes",
      "High acid & zero oxygen destroy decomposers"
    ];

    function selectCard(index) {
      for (let i = 0; i < 3; i++) {
        const card = document.getElementById('card-' + i);
        if (i === index) {
          card.classList.add('active');
        } else {
          card.classList.remove('active');
        }
      }
      document.getElementById('detail-text').textContent = descriptions[index];
    }
  </script>
</body>
</html>

Evidence for Evolution: The Fossil Record

<!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">
  <title>Fossil Types</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: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      width: 100%;
      min-height: 100%;
      justify-content: center;
    }

    .fossil-grid {
      display: flex;
      flex-direction: column;
      gap: 10px;
      width: 100%;
      max-width: 600px;
      margin: 0 auto;
    }

    .fossil-panel {
      display: grid;
      grid-template-columns: 140px 1fr;
      align-items: center;
      gap: 12px;
      padding: 10px 14px;
      border-radius: 12px;
      border: 1px solid rgba(0, 0, 0, 0.06);
      transition: box-shadow 0.2s ease, transform 0.2s ease;
      cursor: pointer;
      user-select: none;
    }

    .fossil-panel:active {
      transform: scale(0.99);
    }

    .panel-impression {
      background: #fffbeb;
      border-color: #fde68a;
    }
    .panel-impression.active {
      box-shadow: 0 0 0 2px #d97706;
    }

    .panel-mould {
      background: #eff6ff;
      border-color: #bfdbfe;
    }
    .panel-mould.active {
      box-shadow: 0 0 0 2px #2563eb;
    }

    .panel-cast {
      background: #f0fdf4;
      border-color: #bbf7d0;
    }
    .panel-cast.active {
      box-shadow: 0 0 0 2px #16a34a;
    }

    .svg-wrap {
      width: 100%;
      height: 90px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .svg-wrap svg {
      width: 100%;
      height: 100%;
      max-height: 90px;
    }

    .info {
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .title {
      font-size: 16px;
      font-weight: 700;
      line-height: 1.2;
    }

    .sub {
      font-size: 13px;
      font-weight: 500;
      color: #64748b;
    }

    .badge {
      display: inline-block;
      align-self: flex-start;
      margin-top: 4px;
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      padding: 2px 8px;
      border-radius: 6px;
    }

    .panel-impression .badge {
      background: #fef3c7;
      color: #92400e;
    }

    .panel-mould .badge {
      background: #dbeafe;
      color: #1e40af;
    }

    .panel-cast .badge {
      background: #dcfce7;
      color: #166534;
    }

    @media (max-width: 420px) {
      .fossil-panel {
        grid-template-columns: 110px 1fr;
        padding: 8px 10px;
        gap: 10px;
      }
      .svg-wrap {
        height: 75px;
      }
      .title {
        font-size: 14px;
      }
      .sub {
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  <div class="fossil-grid">

    
    <div class="fossil-panel panel-impression active" onclick="selectPanel(this)">
      <div class="svg-wrap">
        <svg viewBox="0 0 160 100" fill="none" xmlns="http://www.w3.org/2000/svg">
          
          <polygon points="15,45 125,25 145,55 35,80" fill="#fde68a" stroke="#d97706" stroke-width="1.5" stroke-linejoin="round"/>
          <polygon points="35,80 145,55 145,70 35,95" fill="#f59e0b" stroke="#d97706" stroke-width="1.5" stroke-linejoin="round"/>
          <polygon points="15,45 35,80 35,95 15,60" fill="#d97706" stroke="#b45309" stroke-width="1.5" stroke-linejoin="round"/>

          
          
          <path d="M 75,45 C 70,36 68,34 67,37 C 69,45 74,49 76,57 
                   C 72,52 64,44 61,46 C 60,50 68,58 77,61 
                   C 80,64 85,67 87,63 C 88,59 84,54 83,50 
                   C 89,45 96,38 94,36 C 91,35 84,43 80,48 Z" 
                fill="#b45309" opacity="0.85"/>
          
          <path d="M 76,47 C 72,39 70,37 69,39 C 71,46 75,50 77,57 
                   C 74,53 67,46 64,48 C 63,51 70,58 78,61 
                   C 81,63 84,65 86,62 C 87,58 83,54 82,51 
                   C 87,47 93,41 91,39 C 89,38 83,45 79,49 Z" 
                fill="#78350f"/>
        </svg>
      </div>
      <div class="info">
        <div class="title">Impression</div>
        <div class="sub">Surface Trace</div>
        <div class="badge">2D Print</div>
      </div>
    </div>

    
    <div class="fossil-panel panel-mould" onclick="selectPanel(this)">
      <div class="svg-wrap">
        <svg viewBox="0 0 160 100" fill="none" xmlns="http://www.w3.org/2000/svg">
          
          <rect x="15" y="15" width="130" height="70" rx="8" fill="#cbd5e1" stroke="#64748b" stroke-width="1.5"/>
          
          <line x1="15" y1="38" x2="145" y2="38" stroke="#94a3b8" stroke-width="1" stroke-dasharray="4 2"/>
          <line x1="15" y1="62" x2="145" y2="62" stroke="#94a3b8" stroke-width="1" stroke-dasharray="4 2"/>

          
          
          <circle cx="80" cy="50" r="26" fill="#1e293b"/>
          
          <path d="M 80,50 
                   A 4 4 0 0 1 84,50 
                   A 8 8 0 0 1 76,53 
                   A 13 13 0 0 1 89,56 
                   A 18 18 0 0 1 70,61 
                   A 24 24 0 0 1 98,63" 
                stroke="#475569" stroke-width="2.5" fill="none" stroke-linecap="round"/>
          
          <line x1="72" y1="32" x2="77" y2="40" stroke="#334155" stroke-width="1.5"/>
          <line x1="88" y1="28" x2="86" y2="38" stroke="#334155" stroke-width="1.5"/>
          <line x1="102" y1="42" x2="93" y2="46" stroke="#334155" stroke-width="1.5"/>
          <line x1="104" y1="58" x2="93" y2="56" stroke="#334155" stroke-width="1.5"/>
          <line x1="60" y1="58" x2="70" y2="55" stroke="#334155" stroke-width="1.5"/>

          
          <circle cx="80" cy="50" r="26" stroke="#3b82f6" stroke-width="1.5" stroke-dasharray="3 3" fill="none"/>
        </svg>
      </div>
      <div class="info">
        <div class="title">Mould</div>
        <div class="sub">Empty Cavity</div>
        <div class="badge">Hollow Void</div>
      </div>
    </div>

    
    <div class="fossil-panel panel-cast" onclick="selectPanel(this)">
      <div class="svg-wrap">
        <svg viewBox="0 0 160 100" fill="none" xmlns="http://www.w3.org/2000/svg">
          
          <rect x="15" y="15" width="130" height="70" rx="8" fill="#cbd5e1" stroke="#64748b" stroke-width="1.5"/>
          <line x1="15" y1="38" x2="145" y2="38" stroke="#94a3b8" stroke-width="1" stroke-dasharray="4 2"/>
          <line x1="15" y1="62" x2="145" y2="62" stroke="#94a3b8" stroke-width="1" stroke-dasharray="4 2"/>

          
          <circle cx="80" cy="50" r="26" fill="#10b981" stroke="#059669" stroke-width="1.5"/>
          
          
          <path d="M 80,50 
                   A 4 4 0 0 1 84,50 
                   A 8 8 0 0 1 76,53 
                   A 13 13 0 0 1 89,56 
                   A 18 18 0 0 1 70,61 
                   A 24 24 0 0 1 98,63" 
                stroke="#ecfdf5" stroke-width="3" fill="none" stroke-linecap="round"/>
          
          
          <line x1="72" y1="30" x2="77" y2="40" stroke="#a7f3d0" stroke-width="2.5" stroke-linecap="round"/>
          <line x1="88" y1="26" x2="86" y2="38" stroke="#a7f3d0" stroke-width="2.5" stroke-linecap="round"/>
          <line x1="103" y1="42" x2="93" y2="46" stroke="#a7f3d0" stroke-width="2.5" stroke-linecap="round"/>
          <line x1="104" y1="58" x2="93" y2="56" stroke="#a7f3d0" stroke-width="2.5" stroke-linecap="round"/>
          <line x1="60" y1="58" x2="70" y2="55" stroke="#a7f3d0" stroke-width="2.5" stroke-linecap="round"/>

          
          <polygon points="62,38 64,41 67,41 65,43 66,46 63,44 60,46 61,43 59,41 62,41" fill="#ffffff"/>
          <polygon points="94,32 95,34 98,34 96,36 97,38 95,37 93,38 94,36 92,34 94,34" fill="#ffffff"/>
        </svg>
      </div>
      <div class="info">
        <div class="title">Cast</div>
        <div class="sub">Mineral Replica</div>
        <div class="badge">Solid 3D</div>
      </div>
    </div>

  </div>

  <script>
    function selectPanel(panel) {
      document.querySelectorAll('.fossil-panel').forEach(p => p.classList.remove('active'));
      panel.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; }
    body {
      width: 100%;
      min-height: 100%;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: transparent;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
    }

    .header-bar {
      text-align: center;
      margin-bottom: 12px;
      width: 100%;
      max-width: 540px;
    }
    .header-title {
      font-size: 15px;
      font-weight: 800;
      letter-spacing: 0.5px;
      text-transform: uppercase;
      color: #475569;
    }

    .grid-container {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 10px;
      width: 100%;
      max-width: 540px;
    }

    .reason-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      cursor: pointer;
      position: relative;
      overflow: hidden;
      transition: box-shadow 0.25s ease, background-color 0.25s ease;
      user-select: none;
    }

    .reason-card::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      height: 4px;
      background: var(--accent);
    }

    .reason-card:active {
      background: #f8fafc;
    }

    .reason-card.active {
      box-shadow: 0 0 0 2px var(--accent), 0 4px 12px rgba(0,0,0,0.06);
      background: #ffffff;
    }

    .card-num {
      position: absolute;
      top: 8px;
      left: 10px;
      font-size: 11px;
      font-weight: 800;
      color: var(--accent);
      opacity: 0.85;
    }

    .visual-stage {
      width: 100%;
      height: 62px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      margin: 4px 0 6px 0;
    }

    .symbol-box {
      font-size: 26px;
      line-height: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .arrow-flow {
      font-size: 14px;
      color: #94a3b8;
      font-weight: bold;
    }

    .badge-fade {
      font-size: 20px;
      opacity: 0.35;
      filter: grayscale(1);
    }

    .card-title {
      font-size: 13px;
      font-weight: 700;
      color: #0f172a;
      margin-bottom: 3px;
    }

    .card-desc {
      font-size: 11.5px;
      line-height: 1.35;
      color: #64748b;
      max-width: 95%;
    }

    /* Color Themes */
    .theme-soft { --accent: #f59e0b; }
    .theme-rare { --accent: #ef4444; }
    .theme-geo  { --accent: #3b82f6; }
    .theme-deep { --accent: #10b981; }

    /* Interactive Strata Mini Diagram for Card 3 & 4 */
    .strata-mini {
      width: 44px;
      height: 36px;
      border-radius: 4px;
      display: flex;
      flex-direction: column;
      overflow: hidden;
      border: 1px solid #cbd5e1;
    }
    .strata-layer {
      flex: 1;
      width: 100%;
    }

    .status-pill {
      margin-top: 10px;
      font-size: 11px;
      font-weight: 600;
      color: #64748b;
      background: #f1f5f9;
      padding: 4px 10px;
      border-radius: 20px;
      display: inline-flex;
      align-items: center;
      gap: 5px;
    }

    @media (max-width: 380px) {
      .grid-container {
        gap: 8px;
      }
      .reason-card {
        padding: 10px 8px;
      }
      .visual-stage {
        height: 52px;
      }
      .symbol-box {
        font-size: 22px;
      }
      .card-title {
        font-size: 12px;
      }
      .card-desc {
        font-size: 10.5px;
      }
    }
  </style>
</head>
<body>

  <div class="header-bar">
    <div class="header-title">Why the Fossil Record Has Gaps</div>
  </div>

  <div class="grid-container">
    
    <div class="reason-card theme-soft active" onclick="selectCard(this)">
      <span class="card-num">01</span>
      <div class="visual-stage">
        <div class="symbol-box">🪼</div>
        <div class="arrow-flow">→</div>
        <div class="symbol-box badge-fade">💨</div>
      </div>
      <div class="card-title">Soft-Bodied Life</div>
      <div class="card-desc">No bones or shells to mineralise; decay completely</div>
    </div>

    
    <div class="reason-card theme-rare" onclick="selectCard(this)">
      <span class="card-num">02</span>
      <div class="visual-stage">
        <div class="symbol-box">🐟</div>
        <div class="arrow-flow">→</div>
        <div class="symbol-box">🦀</div>
      </div>
      <div class="card-title">Rare Conditions</div>
      <div class="card-desc">Eaten by scavengers or rot before sediment buries them</div>
    </div>

    
    <div class="reason-card theme-geo" onclick="selectCard(this)">
      <span class="card-num">03</span>
      <div class="visual-stage">
        <div class="symbol-box">🌋</div>
        <div class="strata-mini">
          <div class="strata-layer" style="background:#94a3b8;"></div>
          <div class="strata-layer" style="background:#ef4444;"></div>
          <div class="strata-layer" style="background:#475569;"></div>
        </div>
      </div>
      <div class="card-title">Rock Destruction</div>
      <div class="card-desc">Tectonic heat, pressure, and melting destroy strata</div>
    </div>

    
    <div class="reason-card theme-deep" onclick="selectCard(this)">
      <span class="card-num">04</span>
      <div class="visual-stage">
        <div class="symbol-box">🌊</div>
        <div class="arrow-flow">⬇</div>
        <div class="symbol-box">⛏️</div>
      </div>
      <div class="card-title">Still Undiscovered</div>
      <div class="card-desc">Buried deep under mountain rock or ocean floors</div>
    </div>
  </div>

  <div class="status-pill">
    <span>✦</span> Tap a reason to focus
  </div>

  <script>
    function selectCard(el) {
      document.querySelectorAll('.reason-card').forEach(c => c.classList.remove('active'));
      el.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="4:3">
  <script src="{{VENDOR_CDN}}/classace-diagram.js"></script>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, sans-serif;
    }

    body {
      background: transparent;
      color: #1e2945;
      padding: 12px 8px;
    }

    .diagram-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 10px;
      width: 100%;
      max-width: 720px;
      margin: 0 auto;
    }

    @media (max-width: 540px) {
      .diagram-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
      }
    }

    .step-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      cursor: pointer;
      transition: box-shadow 0.25s ease, border-color 0.25s ease;
      position: relative;
    }

    .step-card.active {
      border-color: #22b7ff;
      box-shadow: 0 0 0 2px #22b7ff, 0 4px 12px rgba(34, 183, 255, 0.15);
    }

    .step-header {
      padding: 8px 10px 4px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .badge {
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.3px;
      padding: 2px 8px;
      border-radius: 12px;
      background: #f1f5f9;
      color: #475569;
    }

    .step-card.active .badge {
      background: #22b7ff;
      color: #ffffff;
    }

    .step-title {
      font-size: 13px;
      font-weight: 700;
      color: #0f172a;
      padding: 0 10px 4px;
    }

    .stage-view {
      width: 100%;
      height: 140px;
      position: relative;
      background: #f8fafc;
    }

    .stage-svg {
      width: 100%;
      height: 100%;
      display: block;
    }

    .step-desc {
      font-size: 12px;
      line-height: 1.35;
      color: #475569;
      padding: 6px 10px 10px;
      min-height: 42px;
      background: #ffffff;
    }

    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      margin-top: 12px;
    }

    .btn-ctrl {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #334155;
      padding: 6px 14px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      cursor: pointer;
    }

    .btn-ctrl:active {
      background: #f1f5f9;
    }

    .dots-nav {
      display: flex;
      gap: 6px;
      align-items: center;
    }

    .dot-btn {
      width: 9px;
      height: 9px;
      border-radius: 50%;
      background: #cbd5e1;
      border: none;
      padding: 0;
      cursor: pointer;
    }

    .dot-btn.active {
      background: #22b7ff;
      width: 18px;
      border-radius: 6px;
    }
  </style>
</head>
<body>

  <div class="diagram-grid">
    
    <div class="step-card active" id="card-0">
      <div class="step-header">
        <span class="badge">STEP 1</span>
      </div>
      <div class="step-title">Burial</div>
      <div class="stage-view">
        <svg class="stage-svg" viewBox="0 0 160 140">
          
          <rect x="0" y="0" width="160" height="70" fill="#bae6fd" />
          <path d="M0 10 Q 40 5, 80 10 T 160 10 L 160 0 L 0 0 Z" fill="#7dd3fc" opacity="0.6"/>
          
          
          <rect x="0" y="70" width="160" height="70" fill="#d6c7a1" />
          
          
          <g fill="#bfae80" opacity="0.8">
            <circle cx="35" cy="50" r="2.5"/>
            <circle cx="65" cy="40" r="3"/>
            <circle cx="100" cy="45" r="2"/>
            <circle cx="130" cy="55" r="3.5"/>
            <circle cx="80" cy="62" r="2.5"/>
          </g>

          
          <g transform="translate(45, 75)">
            
            <ellipse cx="35" cy="18" rx="34" ry="14" fill="#fb923c" opacity="0.85"/>
            <polygon points="65,18 80,8 76,28" fill="#fb923c" opacity="0.85"/>
            
            <circle cx="15" cy="14" r="2.5" fill="#ffffff"/>
            <circle cx="14" cy="14" r="1.2" fill="#0f172a"/>
            
            <path d="M18 18 Q 40 18 64 18" stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" fill="none"/>
            <path d="M28 12 L 28 24 M38 10 L 38 26 M48 11 L 48 25 M58 13 L 58 23" stroke="#ffffff" stroke-width="1.8" stroke-linecap="round"/>
          </g>
          
          
          <path d="M 0 95 Q 80 82 160 95 L 160 140 L 0 140 Z" fill="#c2b078" opacity="0.75"/>
        </svg>
      </div>
      <div class="step-desc">Sediment quickly buries dead organism</div>
    </div>

    
    <div class="step-card" id="card-1">
      <div class="step-header">
        <span class="badge">STEP 2</span>
      </div>
      <div class="step-title">Decay</div>
      <div class="stage-view">
        <svg class="stage-svg" viewBox="0 0 160 140">
          
          <rect x="0" y="0" width="160" height="30" fill="#93c5fd" />
          <rect x="0" y="30" width="160" height="35" fill="#e2d9c2" />
          
          
          <rect x="0" y="65" width="160" height="75" fill="#bfae80" />
          
          
          <line x1="0" y1="65" x2="160" y2="65" stroke="#998650" stroke-dasharray="3 3" stroke-width="1.5"/>

          
          <g transform="translate(45, 82)">
            
            <path d="M12 18 C12 12, 22 10, 24 18 C22 22, 14 22, 12 18 Z" fill="#ffffff" stroke="#cbd5e1" stroke-width="1"/>
            <circle cx="16" cy="16" r="1.5" fill="#475569"/>
            
            <path d="M24 18 Q 45 18 66 18" stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" fill="none"/>
            <path d="M30 11 L 30 25 M38 10 L 38 26 M46 10 L 46 26 M54 11 L 54 25 M62 13 L 62 23" stroke="#ffffff" stroke-width="2" stroke-linecap="round"/>
            <polygon points="66,18 76,10 73,26" fill="#ffffff"/>
          </g>

          
          <g stroke="#64748b" stroke-width="1.5" opacity="0.6" fill="none">
            <path d="M35 15 L35 25 M35 25 L32 22 M35 25 L38 22"/>
            <path d="M80 15 L80 25 M80 25 L77 22 M80 25 L83 22"/>
            <path d="M125 15 L125 25 M125 25 L122 22 M125 25 L128 22"/>
          </g>
        </svg>
      </div>
      <div class="step-desc">Soft tissues rot; bones remain buried</div>
    </div>

    
    <div class="step-card" id="card-2">
      <div class="step-header">
        <span class="badge">STEP 3</span>
      </div>
      <div class="step-title">Mineralisation</div>
      <div class="stage-view">
        <svg class="stage-svg" viewBox="0 0 160 140">
          
          <rect x="0" y="0" width="160" height="35" fill="#b09b70" />
          <rect x="0" y="35" width="160" height="40" fill="#917f5a" />
          <rect x="0" y="75" width="160" height="65" fill="#756544" />
          
          <line x1="0" y1="35" x2="160" y2="35" stroke="#5a4e33" stroke-width="1.5"/>
          <line x1="0" y1="75" x2="160" y2="75" stroke="#5a4e33" stroke-width="1.5"/>

          
          <g stroke="#38bdf8" stroke-width="1.5" stroke-dasharray="2 3" opacity="0.85">
            <line x1="30" y1="40" x2="30" y2="85" />
            <line x1="80" y1="40" x2="80" y2="85" />
            <line x1="130" y1="40" x2="130" y2="85" />
          </g>

          
          <g transform="translate(45, 88)">
            
            <path d="M12 18 C12 12, 22 10, 24 18 C22 22, 14 22, 12 18 Z" fill="#64748b" stroke="#38bdf8" stroke-width="1.2"/>
            <circle cx="16" cy="16" r="1.5" fill="#0f172a"/>
            
            <path d="M24 18 Q 45 18 66 18" stroke="#64748b" stroke-width="3" stroke-linecap="round" fill="none"/>
            <path d="M30 11 L 30 25 M38 10 L 38 26 M46 10 L 46 26 M54 11 L 54 25 M62 13 L 62 23" stroke="#64748b" stroke-width="2.5" stroke-linecap="round"/>
            <polygon points="66,18 76,10 73,26" fill="#64748b" stroke="#38bdf8" stroke-width="1"/>

            
            <polygon points="30,8 32,11 30,14 28,11" fill="#38bdf8"/>
            <polygon points="46,7 48,10 46,13 44,10" fill="#38bdf8"/>
            <polygon points="62,10 64,13 62,16 60,13" fill="#38bdf8"/>
            <polygon points="50,22 52,25 50,28 48,25" fill="#38bdf8"/>
          </g>
        </svg>
      </div>
      <div class="step-desc">Minerals seep in and replace bone with rock</div>
    </div>

    
    <div class="step-card" id="card-3">
      <div class="step-header">
        <span class="badge">STEP 4</span>
      </div>
      <div class="step-title">Exposure</div>
      <div class="stage-view">
        <svg class="stage-svg" viewBox="0 0 160 140">
          
          <rect x="0" y="0" width="160" height="140" fill="#fef08a" opacity="0.3"/>
          <circle cx="140" cy="20" r="12" fill="#facc15" opacity="0.8"/>

          
          <path d="M 0 35 Q 60 50 100 85 L 160 100 L 160 140 L 0 140 Z" fill="#a89260"/>
          <path d="M 0 65 Q 50 78 95 105 L 160 115 L 160 140 L 0 140 Z" fill="#8a7548"/>
          <path d="M 0 95 Q 40 105 85 125 L 160 130 L 160 140 L 0 140 Z" fill="#6d5a32"/>

          
          <path d="M 110 35 Q 130 30 150 36" stroke="#94a3b8" stroke-width="1.5" stroke-linecap="round" fill="none" opacity="0.8"/>
          <path d="M 120 45 Q 140 40 158 47" stroke="#94a3b8" stroke-width="1.5" stroke-linecap="round" fill="none" opacity="0.8"/>

          
          <g transform="translate(42, 60) rotate(14)">
            
            <path d="M12 18 C12 12, 22 10, 24 18 C22 22, 14 22, 12 18 Z" fill="#475569" stroke="#1e293b" stroke-width="1"/>
            <circle cx="16" cy="16" r="1.5" fill="#0f172a"/>
            
            <path d="M24 18 Q 45 18 66 18" stroke="#475569" stroke-width="3" stroke-linecap="round" fill="none"/>
            <path d="M30 11 L 30 25 M38 10 L 38 26 M46 10 L 46 26 M54 11 L 54 25 M62 13 L 62 23" stroke="#475569" stroke-width="2.5" stroke-linecap="round"/>
            <polygon points="66,18 76,10 73,26" fill="#475569" stroke="#1e293b" stroke-width="1"/>
          </g>

          
          <circle cx="82" cy="80" r="18" fill="none" stroke="#22b7ff" stroke-width="2" stroke-dasharray="3 2"/>
        </svg>
      </div>
      <div class="step-desc">Uplift & erosion expose fossil at surface</div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn-ctrl" id="playToggle">
      <span id="playIcon">⏸</span>
      <span id="playText">Pause</span>
    </button>
    <div class="dots-nav">
      <button class="dot-btn active" data-idx="0" aria-label="Step 1"></button>
      <button class="dot-btn" data-idx="1" aria-label="Step 2"></button>
      <button class="dot-btn" data-idx="2" aria-label="Step 3"></button>
      <button class="dot-btn" data-idx="3" aria-label="Step 4"></button>
    </div>
  </div>

  <script>
    const cards = [$('#card-0'), $('#card-1'), $('#card-2'), $('#card-3')];
    const dots = $$('.dot-btn');
    const playBtn = $('#playToggle');
    const playIcon = $('#playIcon');
    const playText = $('#playText');

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

    function setStep(idx) {
      currentIndex = idx;
      cards.forEach((card, i) => {
        if (card) card.classList.toggle('active', i === idx);
      });
      dots.forEach((dot, i) => {
        if (dot) dot.classList.toggle('active', i === idx);
      });
    }

    function nextStep() {
      setStep((currentIndex + 1) % 4);
    }

    function startAuto() {
      stopAuto();
      isPlaying = true;
      playIcon.textContent = '⏸';
      playText.textContent = 'Pause';
      timer = setInterval(nextStep, 3200);
    }

    function stopAuto() {
      isPlaying = false;
      playIcon.textContent = '▶';
      playText.textContent = 'Play';
      if (timer) {
        clearInterval(timer);
        timer = null;
      }
    }

    // Bind cards
    cards.forEach((card, i) => {
      if (card) {
        onTap(card, () => {
          setStep(i);
          stopAuto();
        });
      }
    });

    // Bind dots
    dots.forEach((dot, i) => {
      onTap(dot, () => {
        setStep(i);
        stopAuto();
      });
    });

    // Bind Play/Pause
    onTap(playBtn, () => {
      if (isPlaying) {
        stopAuto();
      } else {
        startAuto();
      }
    });

    // Start auto loop
    startAuto();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      padding: 10px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .nav-bar {
      display: flex;
      gap: 6px;
      margin-bottom: 8px;
      background: #e2e8f0;
      padding: 3px;
      border-radius: 8px;
    }

    .nav-btn {
      background: transparent;
      border: none;
      padding: 5px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      border-radius: 6px;
      cursor: pointer;
      box-shadow: none;
      transition: background 0.15s, color 0.15s;
    }

    .nav-btn.active {
      background: #ffffff;
      color: #0284c7;
      box-shadow: 0 1px 2px rgba(0,0,0,0.08);
    }

    .chart-wrapper {
      width: 100%;
      max-width: 560px;
    }

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

    .gen-row {
      transition: opacity 0.3s ease;
    }

    .gen-row.dimmed {
      opacity: 0.22;
    }

    .mean-line {
      stroke-dasharray: 4 3;
      stroke-width: 1.5;
    }

    .label-badge {
      font-size: 12px;
      font-weight: 700;
      fill: #1e2945;
    }

    .mean-val {
      font-size: 12px;
      font-weight: 700;
      fill: #0284c7;
    }

    .selected-tag {
      font-size: 11px;
      font-weight: 700;
      fill: #16a34a;
    }

    .axis-text {
      font-size: 11px;
      fill: #64748b;
      font-weight: 600;
    }
  </style>
</head>
<body>

  <div class="nav-bar">
    <button class="nav-btn active" onclick="showGen('all')">All Generations</button>
    <button class="nav-btn" onclick="showGen(1)">Gen 1</button>
    <button class="nav-btn" onclick="showGen(2)">Gen 2</button>
    <button class="nav-btn" onclick="showGen(10)">Gen 10</button>
  </div>

  <div class="chart-wrapper">
    <svg viewBox="0 0 500 272" id="plotSvg">
      
      <line x1="60" y1="230" x2="480" y2="230" stroke="#cbd5e1" stroke-width="1.5" />
      
      
      
      <line x1="60" y1="230" x2="60" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="60" y="248" text-anchor="middle" class="axis-text">0</text>

      
      <line x1="144" y1="230" x2="144" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="144" y="248" text-anchor="middle" class="axis-text">10</text>

      
      <line x1="228" y1="230" x2="228" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="228" y="248" text-anchor="middle" class="axis-text">20</text>

      
      <line x1="312" y1="230" x2="312" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="312" y="248" text-anchor="middle" class="axis-text">30</text>

      
      <line x1="396" y1="230" x2="396" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="396" y="248" text-anchor="middle" class="axis-text">40</text>

      
      <line x1="480" y1="230" x2="480" y2="236" stroke="#94a3b8" stroke-width="1" />
      <text x="480" y="248" text-anchor="middle" class="axis-text">50</text>

      <text x="270" y="266" text-anchor="middle" class="axis-text" style="font-weight:700; fill:#1e2945;">Milk Yield (L/day)</text>

      
      <g id="row-1" class="gen-row">
        <text x="10" y="60" class="label-badge">Gen 1</text>
        <path id="curve1-base" fill="#e0f2fe" stroke="#38bdf8" stroke-width="2" />
        <path id="curve1-sel" fill="#86efac" stroke="#22c55e" stroke-width="2" />
        <line x1="186" y1="20" x2="186" y2="70" stroke="#0284c7" class="mean-line" />
        <text x="186" y="16" text-anchor="middle" class="mean-val">15 L</text>
        <text x="238" y="42" class="selected-tag">Top 20% ✦</text>
      </g>

      
      <g id="row-2" class="gen-row">
        <text x="10" y="135" class="label-badge">Gen 2</text>
        <path id="curve2-base" fill="#e0f2fe" stroke="#38bdf8" stroke-width="2" />
        <path id="curve2-sel" fill="#86efac" stroke="#22c55e" stroke-width="2" />
        <line x1="245" y1="95" x2="245" y2="145" stroke="#0284c7" class="mean-line" />
        <text x="245" y="91" text-anchor="middle" class="mean-val">22 L</text>
        <text x="295" y="117" class="selected-tag">Top 20% ✦</text>
      </g>

      
      <g id="row-10" class="gen-row">
        <text x="10" y="210" class="label-badge">Gen 10</text>
        <path id="curve10-base" fill="#bae6fd" stroke="#0284c7" stroke-width="2" />
        <line x1="396" y1="170" x2="396" y2="220" stroke="#0284c7" class="mean-line" />
        <text x="396" y="166" text-anchor="middle" class="mean-val">40 L</text>
      </g>
    </svg>
  </div>

  <script>
    function xToPx(liters) {
      return 60 + liters * 8.4;
    }

    function normalPdf(x, mean, sigma) {
      return Math.exp(-0.5 * Math.pow((x - mean) / sigma, 2));
    }

    function generatePath(mean, sigma, baseY, height, xMin, xMax) {
      const step = 0.5;
      let d = `M ${xToPx(xMin)} ${baseY}`;
      for (let x = xMin; x <= xMax; x += step) {
        const px = xToPx(x);
        const py = baseY - normalPdf(x, mean, sigma) * height;
        d += ` L ${px.toFixed(1)} ${py.toFixed(1)}`;
      }
      d += ` L ${xToPx(xMax)} ${baseY} Z`;
      return d;
    }

    // Gen 1: mean 15, sigma 4.2 -> top 20% is x >= 18.5
    document.getElementById('curve1-base').setAttribute('d', generatePath(15, 4.2, 70, 48, 2, 18.5));
    document.getElementById('curve1-sel').setAttribute('d', generatePath(15, 4.2, 70, 48, 18.5, 28));

    // Gen 2: mean 22, sigma 4.2 -> top 20% is x >= 25.5
    document.getElementById('curve2-base').setAttribute('d', generatePath(22, 4.2, 145, 48, 9, 25.5));
    document.getElementById('curve2-sel').setAttribute('d', generatePath(22, 4.2, 145, 48, 25.5, 35));

    // Gen 10: mean 40, sigma 3.8
    document.getElementById('curve10-base').setAttribute('d', generatePath(40, 3.8, 220, 48, 26, 50));

    function showGen(gen) {
      const buttons = document.querySelectorAll('.nav-btn');
      buttons.forEach(btn => btn.classList.remove('active'));

      const rows = [
        { id: 'row-1', key: 1 },
        { id: 'row-2', key: 2 },
        { id: 'row-10', key: 10 }
      ];

      if (gen === 'all') {
        buttons[0].classList.add('active');
        rows.forEach(r => document.getElementById(r.id).classList.remove('dimmed'));
      } else {
        const idx = gen === 1 ? 1 : gen === 2 ? 2 : 3;
        buttons[idx].classList.add('active');
        rows.forEach(r => {
          const el = document.getElementById(r.id);
          if (r.key === gen) {
            el.classList.remove('dimmed');
          } else {
            el.classList.add('dimmed');
          }
        });
      }
    }
  </script>
</body>
</html>

Selective Breeding in Plants and Animals

<!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;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    .header-bar {
      display: flex;
      justify-content: center;
      margin-bottom: 10px;
      width: 100%;
    }

    .btn-action {
      background: #2563eb;
      color: #ffffff;
      border: none;
      border-radius: 20px;
      padding: 8px 18px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      box-shadow: 0 2px 6px rgba(37, 99, 235, 0.25);
      transition: background 0.2s, transform 0.1s;
    }
    .btn-action:active {
      transform: scale(0.97);
    }
    .btn-action.active {
      background: #dc2626;
      box-shadow: 0 2px 6px rgba(220, 38, 38, 0.25);
    }

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

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

    .pop-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 14px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      overflow: hidden;
    }

    .pop-title {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
      margin-bottom: 12px;
      text-align: center;
    }

    .plants-row {
      display: flex;
      justify-content: center;
      align-items: flex-end;
      gap: 8px;
      margin-bottom: 14px;
      width: 100%;
      height: 90px;
    }

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

    .plant-icon {
      font-size: 26px;
      line-height: 1;
      transition: transform 0.4s ease, filter 0.4s ease, opacity 0.4s ease;
    }

    .dna-pill {
      display: flex;
      flex-direction: column;
      gap: 2px;
      padding: 2px;
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 4px;
      width: 14px;
      height: 38px;
      justify-content: space-around;
      align-items: center;
    }

    .allele {
      width: 8px;
      height: 5px;
      border-radius: 1px;
    }

    /* Allele colors */
    .al-blue   { background: #3b82f6; }
    .al-purple { background: #8b5cf6; }
    .al-amber  { background: #f59e0b; }
    .al-green  { background: #10b981; }
    .al-rose   { background: #f43f5e; }
    .al-yellow { background: #eab308; }

    /* Outbreak state styling */
    .outbreak .wilted .plant-icon {
      transform: rotate(65deg) translateY(4px);
      filter: grayscale(0.9) brightness(0.6) sepia(0.6) hue-rotate(-30deg);
      opacity: 0.6;
    }

    .outbreak .resistant .plant-icon {
      transform: scale(1.08);
      filter: drop-shadow(0 0 4px rgba(34, 197, 94, 0.5));
    }

    .pill-badge {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 13px;
      font-weight: 700;
      padding: 6px 14px;
      border-radius: 20px;
      transition: all 0.3s ease;
      width: 100%;
      max-width: 170px;
      text-align: center;
    }

    .pill-neutral {
      background: #e2e8f0;
      color: #475569;
    }

    .pill-success {
      background: #dcfce7;
      color: #15803d;
      border: 1px solid #86efac;
    }

    .pill-danger {
      background: #fee2e2;
      color: #b91c1c;
      border: 1px solid #fca5a5;
    }

    .pathogen-particles {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
      opacity: 0;
      transition: opacity 0.4s ease;
      background: radial-gradient(circle at 50% 30%, rgba(239, 68, 68, 0.12) 0%, transparent 70%);
    }

    .outbreak .pathogen-particles {
      opacity: 1;
    }
  </style>
</head>
<body>

  <div class="header-bar">
    <button id="outbreakBtn" class="btn-action" onclick="toggleOutbreak()">
      <span id="btnIcon">🦠</span>
      <span id="btnText">Release Pathogen</span>
    </button>
  </div>

  <div class="grid-container" id="grid">
    
    <div class="pop-card">
      <div class="pathogen-particles"></div>
      <div class="pop-title">Wild Population</div>
      
      <div class="plants-row">
        
        <div class="plant-col resistant">
          <div class="plant-icon">🌿</div>
          <div class="dna-pill">
            <div class="allele al-blue"></div>
            <div class="allele al-green"></div>
            <div class="allele al-purple"></div>
          </div>
        </div>
        
        <div class="plant-col resistant">
          <div class="plant-icon">🌿</div>
          <div class="dna-pill">
            <div class="allele al-purple"></div>
            <div class="allele al-rose"></div>
            <div class="allele al-blue"></div>
          </div>
        </div>
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌿</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
        
        <div class="plant-col resistant">
          <div class="plant-icon">🌿</div>
          <div class="dna-pill">
            <div class="allele al-green"></div>
            <div class="allele al-blue"></div>
            <div class="allele al-rose"></div>
          </div>
        </div>
        
        <div class="plant-col resistant">
          <div class="plant-icon">🌿</div>
          <div class="dna-pill">
            <div class="allele al-rose"></div>
            <div class="allele al-purple"></div>
            <div class="allele al-green"></div>
          </div>
        </div>
      </div>

      <div id="wildBadge" class="pill-badge pill-neutral">Diverse Alleles</div>
    </div>

    
    <div class="pop-card">
      <div class="pathogen-particles"></div>
      <div class="pop-title">Monoculture Crop</div>
      
      <div class="plants-row">
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌱</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌱</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌱</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌱</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
        
        <div class="plant-col wilted">
          <div class="plant-icon">🌱</div>
          <div class="dna-pill">
            <div class="allele al-yellow"></div>
            <div class="allele al-amber"></div>
            <div class="allele al-yellow"></div>
          </div>
        </div>
      </div>

      <div id="monoBadge" class="pill-badge pill-neutral">Identical Alleles</div>
    </div>
  </div>

  <script>
    let isOutbreak = false;

    function toggleOutbreak() {
      isOutbreak = !isOutbreak;
      const grid = document.getElementById('grid');
      const btn = document.getElementById('outbreakBtn');
      const btnIcon = document.getElementById('btnIcon');
      const btnText = document.getElementById('btnText');
      const wildBadge = document.getElementById('wildBadge');
      const monoBadge = document.getElementById('monoBadge');

      if (isOutbreak) {
        grid.classList.add('outbreak');
        btn.classList.add('active');
        btnIcon.textContent = '↺';
        btnText.textContent = 'Reset Simulation';
        
        wildBadge.className = 'pill-badge pill-success';
        wildBadge.textContent = '✓ 80% Survival';

        monoBadge.className = 'pill-badge pill-danger';
        monoBadge.textContent = '✗ 0% Survival';
      } else {
        grid.classList.remove('outbreak');
        btn.classList.remove('active');
        btnIcon.textContent = '🦠';
        btnText.textContent = 'Release Pathogen';

        wildBadge.className = 'pill-badge pill-neutral';
        wildBadge.textContent = 'Diverse Alleles';

        monoBadge.className = 'pill-badge pill-neutral';
        monoBadge.textContent = 'Identical Alleles';
      }
    }
  </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>Artificial Selection in Brassica oleracea</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      width: 100%;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 10px 14px;
      user-select: none;
    }

    .main-wrapper {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .header-text {
      text-align: center;
      margin-bottom: 2px;
    }

    .header-title {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }

    .header-sub {
      font-size: 11px;
      color: #64748b;
      margin-top: 2px;
    }

    .diagram-container {
      position: relative;
      width: 100%;
    }

    .connectors-svg {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
      z-index: 1;
    }

    .conn-path {
      fill: none;
      stroke: #cbd5e1;
      stroke-width: 2;
      stroke-dasharray: 4 3;
      transition: stroke 0.3s ease, stroke-width 0.3s ease, opacity 0.3s ease;
    }

    .conn-path.active {
      stroke: #10b981;
      stroke-width: 2.5;
      stroke-dasharray: none;
      filter: drop-shadow(0 1px 3px rgba(16, 185, 129, 0.4));
    }

    .diagram-grid {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      grid-template-rows: 1fr 1fr;
      gap: 12px 16px;
      width: 100%;
      align-items: center;
      position: relative;
      z-index: 2;
    }

    .center-card {
      grid-column: 2;
      grid-row: 1 / span 2;
      background: #ffffff;
      border: 2px solid #10b981;
      border-radius: 14px;
      padding: 12px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      text-align: center;
      box-shadow: 0 4px 12px rgba(16, 185, 129, 0.14);
      width: 124px;
      z-index: 3;
    }

    .wild-icon {
      font-size: 30px;
      line-height: 1;
      margin-bottom: 4px;
    }

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

    .wild-sub {
      font-size: 10.5px;
      font-style: italic;
      color: #059669;
      font-weight: 600;
      margin-top: 2px;
    }

    .wild-tag {
      margin-top: 6px;
      background: #ecfdf5;
      color: #047857;
      font-size: 9px;
      font-weight: 700;
      padding: 2px 6px;
      border-radius: 6px;
      text-transform: uppercase;
      letter-spacing: 0.4px;
    }

    .veg-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 10px;
      display: flex;
      align-items: center;
      gap: 9px;
      cursor: pointer;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
      position: relative;
      z-index: 3;
    }

    .veg-card:hover {
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
      border-color: #94a3b8;
    }

    .veg-card.active {
      border-color: #10b981;
      background: #ffffff;
      box-shadow: 0 0 0 1px #10b981, 0 4px 12px rgba(16, 185, 129, 0.15);
    }

    .veg-icon {
      font-size: 26px;
      line-height: 1;
      flex-shrink: 0;
    }

    .veg-info {
      display: flex;
      flex-direction: column;
      min-width: 0;
    }

    .veg-name {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }

    .veg-card.active .veg-name {
      color: #047857;
    }

    .trait-badge {
      font-size: 10.5px;
      color: #64748b;
      font-weight: 500;
      margin-top: 2px;
      line-height: 1.2;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }

    .veg-card.active .trait-badge {
      color: #059669;
      font-weight: 600;
    }

    /* Grid positions */
    .pos-tl { grid-column: 1; grid-row: 1; }
    .pos-bl { grid-column: 1; grid-row: 2; }
    .pos-tr { grid-column: 3; grid-row: 1; }
    .pos-br { grid-column: 3; grid-row: 2; }

    /* Details Panel */
    .details-box {
      background: #ffffff;
      border: 1.5px solid #d1fae5;
      border-radius: 12px;
      padding: 10px 14px;
      box-shadow: 0 2px 6px rgba(16, 185, 129, 0.08);
      position: relative;
    }

    .details-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 4px;
    }

    .details-title-group {
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .details-icon {
      font-size: 16px;
    }

    .details-title {
      font-size: 13px;
      font-weight: 700;
      color: #065f46;
    }

    .details-badge {
      font-size: 10px;
      font-weight: 600;
      background: #ecfdf5;
      color: #047857;
      padding: 2px 7px;
      border-radius: 10px;
      border: 1px solid #a7f3d0;
    }

    .details-desc {
      font-size: 11.5px;
      line-height: 1.45;
      color: #334155;
    }

    .details-desc strong {
      color: #0f172a;
    }

    @media (max-width: 440px) {
      .diagram-grid {
        grid-template-columns: 1fr 1fr;
        grid-template-rows: auto auto auto;
        gap: 8px;
      }
      .center-card {
        grid-column: 1 / span 2;
        grid-row: 1;
        width: 100%;
        flex-direction: row;
        gap: 10px;
        padding: 6px 12px;
      }
      .wild-icon { margin-bottom: 0; font-size: 24px; }
      .wild-tag { margin-top: 0; margin-left: 6px; display: inline-block; }
      .pos-tl { grid-column: 1; grid-row: 2; }
      .pos-tr { grid-column: 2; grid-row: 2; }
      .pos-bl { grid-column: 1; grid-row: 3; }
      .pos-br { grid-column: 2; grid-row: 3; }
      .veg-card { padding: 7px 8px; gap: 6px; }
      .veg-icon { font-size: 22px; }
      .veg-name { font-size: 12px; }
      .trait-badge { font-size: 9.5px; }
      .details-box { padding: 8px 10px; }
      .details-desc { font-size: 11px; }
    }
  </style>
</head>
<body>

  <div class="main-wrapper">
    <div class="header-text">
      <div class="header-title">Artificial Selection from Wild Mustard</div>
      <div class="header-sub">Click a vegetable to explore the trait farmers selectively bred</div>
    </div>

    <div class="diagram-container" id="diagramContainer">
      <svg class="connectors-svg" id="connectorsSvg">
        <path id="line-0" class="conn-path"></path>
        <path id="line-1" class="conn-path"></path>
        <path id="line-2" class="conn-path"></path>
        <path id="line-3" class="conn-path"></path>
      </svg>

      <div class="diagram-grid">
        
        <div class="center-card" id="centerCard">
          <div class="wild-icon">🌱</div>
          <div>
            <div class="wild-title">Wild Mustard</div>
            <div class="wild-sub">Brassica oleracea</div>
            <div class="wild-tag">Ancestor</div>
          </div>
        </div>

        
        <div class="veg-card pos-tl active" data-index="0">
          <div class="veg-icon">🥬</div>
          <div class="veg-info">
            <span class="veg-name">Kale</span>
            <span class="trait-badge">Enlarged leaves</span>
          </div>
        </div>

        
        <div class="veg-card pos-bl" data-index="1">
          <div class="veg-icon">🪴</div>
          <div class="veg-info">
            <span class="veg-name">Kohlrabi</span>
            <span class="trait-badge">Swollen stem</span>
          </div>
        </div>

        
        <div class="veg-card pos-tr" data-index="2">
          <div class="veg-icon">🥦</div>
          <div class="veg-info">
            <span class="veg-name">Broccoli</span>
            <span class="trait-badge">Flower buds & stems</span>
          </div>
        </div>

        
        <div class="veg-card pos-br" data-index="3">
          <div class="veg-icon">🥗</div>
          <div class="veg-info">
            <span class="veg-name">Cabbage</span>
            <span class="trait-badge">Terminal bud</span>
          </div>
        </div>
      </div>
    </div>

    
    <div class="details-box">
      <div class="details-header">
        <div class="details-title-group">
          <span class="details-icon" id="detailIcon">🥬</span>
          <span class="details-title" id="detailName">Kale</span>
        </div>
        <span class="details-badge" id="detailTrait">Target Trait: Enlarged Leaves</span>
      </div>
      <div class="details-desc" id="detailDesc">
        <strong>Selection Purpose:</strong> Farmers selected and propagated mustard plants with larger, broader, and more nutritious leaves over generations, resulting in hardy leafy green foliage.
      </div>
    </div>
  </div>

  <script>
    const vegData = [
      {
        name: "Kale",
        icon: "🥬",
        trait: "Target Trait: Enlarged Leaves",
        desc: "Farmers selected and propagated wild mustard plants with larger, broader, and more nutritious leaves over generations, resulting in hardy, nutrient-dense leafy greens."
      },
      {
        name: "Kohlrabi",
        icon: "🪴",
        trait: "Target Trait: Swollen Stem",
        desc: "Breeders selected plants that developed thick, bulbous stems above ground, creating a crisp, juicy turnip-like vegetable rich in vitamin C and dietary fiber."
      },
      {
        name: "Broccoli",
        icon: "🥦",
        trait: "Target Trait: Flower Buds & Stems",
        desc: "Selected by arresting floral development to create dense clusters of immature flower buds and tender, edible flower stalks before they bloom into yellow petals."
      },
      {
        name: "Cabbage",
        icon: "🥗",
        trait: "Target Trait: Enlarged Terminal Bud",
        desc: "Selected for extremely short internode spacing between leaves and an oversized terminal bud, forming tightly packed, compact heads ideal for long storage."
      }
    ];

    const cards = document.querySelectorAll('.veg-card');
    const centerCard = document.getElementById('centerCard');
    const container = document.getElementById('diagramContainer');
    const detailIcon = document.getElementById('detailIcon');
    const detailName = document.getElementById('detailName');
    const detailTrait = document.getElementById('detailTrait');
    const detailDesc = document.getElementById('detailDesc');

    let currentIndex = 0;
    let autoPlayTimer = null;

    function updateConnectors() {
      const containerRect = container.getBoundingClientRect();
      const centerRect = centerCard.getBoundingClientRect();
      const isStacked = window.innerWidth <= 440;

      const cMidX = (centerRect.left + centerRect.right) / 2 - containerRect.left;
      const cMidY = (centerRect.top + centerRect.bottom) / 2 - containerRect.top;

      cards.forEach((card, idx) => {
        const line = document.getElementById(`line-${idx}`);
        if (!line) return;

        const cardRect = card.getBoundingClientRect();
        const cardMidX = (cardRect.left + cardRect.right) / 2 - containerRect.left;
        const cardMidY = (cardRect.top + cardRect.bottom) / 2 - containerRect.top;

        let startX, startY, endX, endY;

        if (isStacked) {
          startX = cMidX;
          startY = centerRect.bottom - containerRect.top;
          endX = cardMidX;
          endY = cardRect.top - containerRect.top;
          line.setAttribute('d', `M ${startX} ${startY} Q ${startX} ${(startY + endY) / 2}, ${endX} ${endY}`);
        } else {
          if (cardMidX < cMidX) {
            startX = centerRect.left - containerRect.left;
            startY = cMidY;
            endX = cardRect.right - containerRect.left;
            endY = cardMidY;
          } else {
            startX = centerRect.right - containerRect.left;
            startY = cMidY;
            endX = cardRect.left - containerRect.left;
            endY = cardMidY;
          }
          const controlX = (startX + endX) / 2;
          line.setAttribute('d', `M ${startX} ${startY} C ${controlX} ${startY}, ${controlX} ${endY}, ${endX} ${endY}`);
        }

        line.classList.toggle('active', idx === currentIndex);
      });
    }

    function selectCard(index) {
      currentIndex = index;
      cards.forEach((c, i) => {
        c.classList.toggle('active', i === index);
      });

      const data = vegData[index];
      detailIcon.textContent = data.icon;
      detailName.textContent = data.name;
      detailTrait.textContent = data.trait;
      detailDesc.innerHTML = `<strong>Selection Purpose:</strong> ${data.desc}`;

      updateConnectors();
    }

    cards.forEach((card, idx) => {
      card.addEventListener('click', () => {
        clearInterval(autoPlayTimer);
        selectCard(idx);
      });
    });

    window.addEventListener('resize', updateConnectors);
    window.addEventListener('load', updateConnectors);

    // Initial connector setup
    requestAnimationFrame(updateConnectors);

    // Gentle auto-cycle every 4 seconds
    autoPlayTimer = setInterval(() => {
      currentIndex = (currentIndex + 1) % cards.length;
      selectCard(currentIndex);
    }, 4000);
  </script>
</body>
</html>

UK-GCSE-SCIENCE-BIO-IVE

Child standards (5)

Aligned learning resources

Related diagrams