<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 12px 10px;
      gap: 12px;
      width: 100%;
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      width: 100%;
      max-width: 480px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn {
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      border: 1.5px solid #d1d5db;
      background: #f8fafc;
      color: #1e2945;
      border-radius: 20px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
    }
    .btn:hover {
      background: #eef2f6;
      border-color: #94a3b8;
    }
    .btn.active {
      background: #22b7ff;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 8px rgba(34, 183, 255, 0.4);
    }

    /* Main Diagram Area */
    .diagram-area {
      position: relative;
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }

    /* Top Branches */
    .branches {
      display: flex;
      width: 100%;
      gap: 12px;
      justify-content: space-between;
    }
    .branch-card {
      flex: 1;
      min-width: 0;
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      gap: 6px;
      transition: opacity 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
    }
    .branch-card.dimmed {
      opacity: 0.7;
      border-color: #e2e8f0;
      background: #fafafa;
    }
    .branch-card.highlight {
      opacity: 1;
      border-color: #22b7ff;
      background: #ffffff;
      box-shadow: 0 3px 12px rgba(34, 183, 255, 0.22);
    }

    .card-title {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }
    .card-sub {
      font-size: 11px;
      color: #475569;
      font-weight: 600;
    }

    /* Plant Cells Display */
    .cell-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 3px;
      width: 100%;
      max-width: 120px;
      height: 56px;
      padding: 4px;
      background: #e8f5e9;
      border: 1.5px solid #81c784;
      border-radius: 6px;
    }
    .plant-cell {
      background: #c8e6c9;
      border: 1.5px solid #2e7d32;
      border-radius: 2px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .plant-cell::after {
      content: '';
      width: 5px;
      height: 5px;
      background: #1b5e20;
      border-radius: 50%;
    }

    /* Animal Cells Display */
    .cell-cluster {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
      gap: 4px;
      width: 100%;
      max-width: 120px;
      height: 56px;
      padding: 4px;
      background: #fce4ec;
      border: 1.5px solid #f48fb1;
      border-radius: 6px;
    }
    .animal-cell {
      width: 24px;
      height: 20px;
      background: #f8bbd0;
      border: 1.5px solid #c2185b;
      border-radius: 50% 60% 45% 55%;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .animal-cell.long {
      width: 38px;
      height: 18px;
      border-radius: 12px 16px 14px 10px;
    }
    .animal-cell::after {
      content: '';
      width: 4px;
      height: 4px;
      background: #880e4f;
      border-radius: 50%;
    }

    /* Merge Connector */
    .connector-svg {
      width: 100%;
      max-width: 320px;
      height: 34px;
      overflow: visible;
    }
    .path-arrow {
      stroke: #94a3b8;
      stroke-width: 2.5;
      fill: none;
      transition: stroke 0.25s ease, stroke-width 0.25s ease;
    }
    .path-arrow.active {
      stroke: #22b7ff;
      stroke-width: 3;
      stroke-dasharray: 6 3;
      animation: dash 1s linear infinite;
    }
    @keyframes dash {
      to { stroke-dashoffset: -9; }
    }

    /* Synthesis Badge */
    .badge-card {
      width: 100%;
      background: #ffffff;
      border: 2px solid #cbd5e1;
      border-radius: 12px;
      padding: 12px 14px;
      text-align: center;
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all 0.25s ease;
    }
    .badge-card.dimmed {
      opacity: 0.75;
      background: #f8fafc;
      border-color: #cbd5e1;
      color: #334155;
    }
    .badge-card.glowing {
      opacity: 1;
      background: #f0faff;
      border-color: #22b7ff;
      color: #0c4a6e;
      box-shadow: 0 0 16px rgba(34, 183, 255, 0.35);
    }
    .badge-icon {
      font-size: 16px;
      color: #22b7ff;
      flex-shrink: 0;
    }
    .badge-text {
      line-height: 1.3;
    }

    @media (max-width: 380px) {
      .btn {
        font-size: 12px;
        padding: 5px 10px;
      }
      .card-title {
        font-size: 12px;
      }
      .card-sub {
        font-size: 10px;
      }
      .badge-card {
        font-size: 13px;
        padding: 10px 10px;
      }
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="btn" id="btn-0" onclick="setStep(0)">🌿 Schleiden</button>
    <button class="btn" id="btn-1" onclick="setStep(1)">🐾 Schwann</button>
    <button class="btn" id="btn-2" onclick="setStep(2)">✦ Unified Idea</button>
  </div>

  <div class="diagram-area">
    
    <div class="branches">
      <div class="branch-card" id="card-left">
        <div class="card-title">Schleiden (1838)</div>
        <div class="card-sub">Plant Cells</div>
        <div class="cell-grid">
          <div class="plant-cell"></div>
          <div class="plant-cell"></div>
          <div class="plant-cell"></div>
          <div class="plant-cell"></div>
          <div class="plant-cell"></div>
          <div class="plant-cell"></div>
        </div>
      </div>

      <div class="branch-card" id="card-right">
        <div class="card-title">Schwann (1839)</div>
        <div class="card-sub">Animal Cells</div>
        <div class="cell-cluster">
          <div class="animal-cell"></div>
          <div class="animal-cell long"></div>
          <div class="animal-cell"></div>
          <div class="animal-cell long"></div>
        </div>
      </div>
    </div>

    
    <svg class="connector-svg" viewBox="0 0 300 36">
      <defs>
        <marker id="arrow-active" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1 L 8 5 L 0 9 z" fill="#22b7ff" />
        </marker>
        <marker id="arrow-idle" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1 L 8 5 L 0 9 z" fill="#94a3b8" />
        </marker>
      </defs>
      <path id="arrow-left" class="path-arrow" d="M 55 2 C 55 22, 140 12, 145 30" marker-end="url(#arrow-idle)" />
      <path id="arrow-right" class="path-arrow" d="M 245 2 C 245 22, 160 12, 155 30" marker-end="url(#arrow-idle)" />
    </svg>

    
    <div class="badge-card" id="badge">
      <span class="badge-icon">✦</span>
      <span class="badge-text">All living organisms are made of cells!</span>
    </div>
  </div>

  <script>
    let currentStep = 2;
    let timer = null;

    function render() {
      const cardLeft = document.getElementById('card-left');
      const cardRight = document.getElementById('card-right');
      const arrowLeft = document.getElementById('arrow-left');
      const arrowRight = document.getElementById('arrow-right');
      const badge = document.getElementById('badge');

      // Update buttons
      for (let i = 0; i < 3; i++) {
        document.getElementById(`btn-${i}`).classList.toggle('active', i === currentStep);
      }

      if (currentStep === 0) {
        cardLeft.className = 'branch-card highlight';
        cardRight.className = 'branch-card dimmed';
        arrowLeft.className = 'path-arrow';
        arrowLeft.setAttribute('marker-end', 'url(#arrow-idle)');
        arrowRight.className = 'path-arrow';
        arrowRight.setAttribute('marker-end', 'url(#arrow-idle)');
        badge.className = 'badge-card dimmed';
      } else if (currentStep === 1) {
        cardLeft.className = 'branch-card dimmed';
        cardRight.className = 'branch-card highlight';
        arrowLeft.className = 'path-arrow';
        arrowLeft.setAttribute('marker-end', 'url(#arrow-idle)');
        arrowRight.className = 'path-arrow';
        arrowRight.setAttribute('marker-end', 'url(#arrow-idle)');
        badge.className = 'badge-card dimmed';
      } else {
        cardLeft.className = 'branch-card highlight';
        cardRight.className = 'branch-card highlight';
        arrowLeft.className = 'path-arrow active';
        arrowLeft.setAttribute('marker-end', 'url(#arrow-active)');
        arrowRight.className = 'path-arrow active';
        arrowRight.setAttribute('marker-end', 'url(#arrow-active)');
        badge.className = 'badge-card glowing';
      }
    }

    function setStep(step) {
      currentStep = step;
      render();
      resetAutoplay();
    }

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

    function resetAutoplay() {
      clearInterval(timer);
      timer = setInterval(nextStep, 3500);
    }

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

History and Tenets of Cell Theory

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Spontaneous Generation vs Cell Division</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: #ffffff;
      padding: 12px;
      display: flex;
      flex-direction: column;
      height: 100%;
      min-height: 100%;
      justify-content: space-between;
      user-select: none;
      -webkit-user-select: none;
    }
    .panels-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      flex: 1;
      min-height: 0;
    }
    @media (max-width: 480px) {
      .panels-grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }
    .panel-card {
      background: #ffffff;
      border: 1px solid #d1d5db;
      border-radius: 12px;
      padding: 10px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      position: relative;
      overflow: hidden;
    }
    .badge {
      display: inline-flex;
      align-items: center;
      gap: 5px;
      font-size: 13px;
      font-weight: 700;
      padding: 5px 12px;
      border-radius: 20px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }
    .badge-myth {
      background: #fee2e2;
      color: #991b1b;
      border: 1px solid #f87171;
    }
    .badge-reality {
      background: #dcfce7;
      color: #14532d;
      border: 1px solid #4ade80;
    }
    .stage-view {
      flex: 1;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      min-height: 140px;
    }
    .caption {
      font-size: 13px;
      font-weight: 600;
      color: #0f172a;
      margin-top: 4px;
      text-align: center;
      min-height: 36px;
      display: flex;
      align-items: center;
      justify-content: center;
      line-height: 1.3;
    }
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-top: 10px;
      padding-top: 6px;
      flex-wrap: wrap;
    }
    .btn-step {
      background: #f8fafc;
      border: 1px solid #94a3b8;
      color: #0f172a;
      padding: 7px 14px;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      transition: background 0.2s, border-color 0.2s, color 0.2s;
    }
    .btn-step:hover {
      background: #e2e8f0;
      border-color: #64748b;
    }
    .btn-step.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0369a1;
    }
    .btn-play {
      background: #f8fafc;
      border: 1px solid #94a3b8;
      color: #0f172a;
      width: 36px;
      height: 34px;
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 14px;
      font-weight: bold;
      cursor: pointer;
      transition: background 0.2s, border-color 0.2s;
    }
    .btn-play:hover {
      background: #e2e8f0;
      border-color: #64748b;
    }
    svg {
      width: 100%;
      height: 100%;
      max-height: 170px;
      overflow: visible;
    }

    /* Animated SVG Elements */
    #mythCreature {
      transition: transform 0.6s cubic-bezier(0.34, 1.4, 0.64, 1), opacity 0.5s ease;
      transform-origin: 100px 68px;
    }
    #redX {
      transition: transform 0.45s cubic-bezier(0.34, 1.5, 0.64, 1), opacity 0.35s ease;
      transform-origin: 100px 68px;
    }
    #greenCheck {
      transition: transform 0.45s cubic-bezier(0.34, 1.5, 0.64, 1), opacity 0.35s ease;
      transform-origin: 100px 75px;
    }
    #cellLeft, #cellRight {
      transition: transform 0.65s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.45s ease;
    }
    #bodyLeft, #bodyRight {
      transition: rx 0.65s ease, ry 0.65s ease;
    }
    #nucLeft, #nucRight {
      transition: transform 0.65s ease, r 0.65s ease;
    }
    @keyframes bubbleFloat {
      0%, 100% { transform: translateY(0); opacity: 0.4; }
      50% { transform: translateY(-7px); opacity: 0.9; }
    }
    .bubble-1 { animation: bubbleFloat 2.2s ease-in-out infinite; }
    .bubble-2 { animation: bubbleFloat 2.5s ease-in-out infinite 0.8s; }
  </style>
</head>
<body>

  <div class="panels-grid" id="panelsContainer">
    
    <div class="panel-card">
      <span class="badge badge-myth">✕ Myth</span>
      <div class="stage-view">
        <svg viewBox="0 0 200 150">
          
          <ellipse cx="100" cy="118" rx="80" ry="22" fill="#d97706" opacity="0.2" />
          <path d="M 28 116 Q 60 96 100 106 Q 145 92 172 116 Q 140 136 100 130 Q 50 136 28 116 Z" fill="#92400e" />
          <ellipse cx="75" cy="114" rx="14" ry="5" fill="#78350f" />
          <ellipse cx="130" cy="120" rx="18" ry="6" fill="#78350f" />
          
          
          <circle class="bubble-1" cx="95" cy="106" r="4.5" fill="#b45309" />
          <circle class="bubble-2" cx="125" cy="112" r="3.5" fill="#b45309" />
          
          
          <g id="mythCreature" transform="translate(100, 110) scale(0)" opacity="0">
            <ellipse cx="0" cy="0" rx="16" ry="12" fill="#64748b" />
            <circle cx="-14" cy="-2" r="7" fill="#475569" />
            
            <path d="M -4 -8 Q -10 -25 8 -18 Z" fill="#94a3b8" opacity="0.85" />
            <path d="M 4 -8 Q 15 -25 18 -14 Z" fill="#94a3b8" opacity="0.85" />
            
            <line x1="-8" y1="8" x2="-14" y2="18" stroke="#334155" stroke-width="2.5" stroke-linecap="round" />
            <line x1="0" y1="10" x2="0" y2="20" stroke="#334155" stroke-width="2.5" stroke-linecap="round" />
            <line x1="8" y1="8" x2="14" y2="18" stroke="#334155" stroke-width="2.5" stroke-linecap="round" />
          </g>

          
          <g id="redX" transform="translate(100, 68) scale(0)" opacity="0">
            <circle cx="0" cy="0" r="28" fill="#fee2e2" stroke="#dc2626" stroke-width="3.5" />
            <line x1="-13" y1="-13" x2="13" y2="13" stroke="#991b1b" stroke-width="4.5" stroke-linecap="round" />
            <line x1="13" y1="-13" x2="-13" y2="13" stroke="#991b1b" stroke-width="4.5" stroke-linecap="round" />
          </g>
        </svg>
      </div>
      <div class="caption" id="mythCaption">Non-living mud puddle</div>
    </div>

    
    <div class="panel-card">
      <span class="badge badge-reality">✓ Reality</span>
      <div class="stage-view">
        <svg viewBox="0 0 200 150">
          <defs>
            <radialGradient id="cellGrad" cx="35%" cy="35%">
              <stop offset="0%" stop-color="#bae6fd" />
              <stop offset="100%" stop-color="#38bdf8" />
            </radialGradient>
            <radialGradient id="nucGrad" cx="35%" cy="35%">
              <stop offset="0%" stop-color="#0284c7" />
              <stop offset="100%" stop-color="#0369a1" />
            </radialGradient>
          </defs>

          
          <g id="cellGroup" transform="translate(100, 75)">
            
            <g id="cellLeft" transform="translate(0, 0)">
              <ellipse id="bodyLeft" cx="0" cy="0" rx="34" ry="34" fill="url(#cellGrad)" stroke="#0284c7" stroke-width="2.5" />
              <circle id="nucLeft" cx="0" cy="0" r="11" fill="url(#nucGrad)" />
            </g>
            
            <g id="cellRight" transform="translate(0, 0)" opacity="0">
              <ellipse id="bodyRight" cx="0" cy="0" rx="34" ry="34" fill="url(#cellGrad)" stroke="#0284c7" stroke-width="2.5" />
              <circle id="nucRight" cx="0" cy="0" r="11" fill="url(#nucGrad)" />
            </g>
          </g>

          
          <g id="greenCheck" transform="translate(100, 75) scale(0)" opacity="0">
            <circle cx="0" cy="0" r="28" fill="#dcfce7" stroke="#16a34a" stroke-width="3.5" />
            <polyline points="-12,-1 -3,8 14,-9" fill="none" stroke="#14532d" stroke-width="4.5" stroke-linecap="round" stroke-linejoin="round" />
          </g>
        </svg>
      </div>
      <div class="caption" id="realityCaption">1 Parent Cell</div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn-play" id="playToggle" title="Play/Pause" aria-label="Play or pause animation">⏸</button>
    <button class="btn-step active" data-step="0">1. Start</button>
    <button class="btn-step" data-step="1">2. Process</button>
    <button class="btn-step" data-step="2">3. Result</button>
  </div>

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

    // DOM Elements
    const mythCreature = document.getElementById('mythCreature');
    const redX = document.getElementById('redX');
    const cellLeft = document.getElementById('cellLeft');
    const cellRight = document.getElementById('cellRight');
    const bodyLeft = document.getElementById('bodyLeft');
    const bodyRight = document.getElementById('bodyRight');
    const nucLeft = document.getElementById('nucLeft');
    const nucRight = document.getElementById('nucRight');
    const greenCheck = document.getElementById('greenCheck');

    const mythCaption = document.getElementById('mythCaption');
    const realityCaption = document.getElementById('realityCaption');

    const stepBtns = document.querySelectorAll('.btn-step');
    const playToggle = document.getElementById('playToggle');

    const captions = [
      {
        myth: "Step 1: Non-living mud puddle",
        reality: "Step 1: 1 single parent cell"
      },
      {
        myth: "Step 2: Myth claimed life appears from mud",
        reality: "Step 2: Cell duplicates DNA & stretches"
      },
      {
        myth: "Result: ✕ Disproven! Life cannot form from non-life",
        reality: "Result: ✓ 2 identical daughter cells divide"
      }
    ];

    function setStep(step) {
      currentStep = step;

      // Update captions
      mythCaption.textContent = captions[step].myth;
      realityCaption.textContent = captions[step].reality;

      // Update button active state
      stepBtns.forEach((btn, idx) => {
        btn.classList.toggle('active', idx === step);
      });

      if (step === 0) {
        // Step 0: Start state
        mythCreature.style.transform = "translate(100px, 110px) scale(0)";
        mythCreature.style.opacity = "0";

        redX.style.transform = "translate(100px, 68px) scale(0)";
        redX.style.opacity = "0";

        cellLeft.style.transform = "translate(0px, 0px)";
        cellRight.style.transform = "translate(0px, 0px)";
        cellRight.style.opacity = "0";

        bodyLeft.setAttribute('rx', '34');
        bodyLeft.setAttribute('ry', '34');
        bodyRight.setAttribute('rx', '34');
        bodyRight.setAttribute('ry', '34');

        nucLeft.style.transform = "translate(0px, 0px)";
        nucRight.style.transform = "translate(0px, 0px)";
        nucLeft.setAttribute('r', '11');
        nucRight.setAttribute('r', '11');

        greenCheck.style.transform = "translate(100px, 75px) scale(0)";
        greenCheck.style.opacity = "0";

      } else if (step === 1) {
        // Step 1: Process state
        mythCreature.style.transform = "translate(100px, 68px) scale(1)";
        mythCreature.style.opacity = "0.95";

        redX.style.transform = "translate(100px, 68px) scale(0)";
        redX.style.opacity = "0";

        cellLeft.style.transform = "translate(-14px, 0px)";
        cellRight.style.transform = "translate(14px, 0px)";
        cellRight.style.opacity = "0.9";

        bodyLeft.setAttribute('rx', '40');
        bodyLeft.setAttribute('ry', '28');
        bodyRight.setAttribute('rx', '40');
        bodyRight.setAttribute('ry', '28');

        nucLeft.style.transform = "translate(-12px, 0px)";
        nucRight.style.transform = "translate(12px, 0px)";
        nucLeft.setAttribute('r', '9.5');
        nucRight.setAttribute('r', '9.5');

        greenCheck.style.transform = "translate(100px, 75px) scale(0)";
        greenCheck.style.opacity = "0";

      } else if (step === 2) {
        // Step 2: Result state
        mythCreature.style.transform = "translate(100px, 68px) scale(0.95)";
        mythCreature.style.opacity = "0.25";

        redX.style.transform = "translate(100px, 68px) scale(1)";
        redX.style.opacity = "1";

        cellLeft.style.transform = "translate(-44px, 0px)";
        cellRight.style.transform = "translate(44px, 0px)";
        cellRight.style.opacity = "1";

        bodyLeft.setAttribute('rx', '25');
        bodyLeft.setAttribute('ry', '25');
        bodyRight.setAttribute('rx', '25');
        bodyRight.setAttribute('ry', '25');

        nucLeft.style.transform = "translate(0px, 0px)";
        nucRight.style.transform = "translate(0px, 0px)";
        nucLeft.setAttribute('r', '8.5');
        nucRight.setAttribute('r', '8.5');

        greenCheck.style.transform = "translate(100px, 75px) scale(1)";
        greenCheck.style.opacity = "1";
      }
    }

    function startAutoPlay() {
      stopAutoPlay();
      isPlaying = true;
      playToggle.textContent = '⏸';
      autoTimer = setInterval(() => {
        const next = (currentStep + 1) % 3;
        setStep(next);
      }, 2600);
    }

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

    // Step button click handlers
    stepBtns.forEach((btn) => {
      btn.addEventListener('click', () => {
        const step = parseInt(btn.getAttribute('data-step'), 10);
        stopAutoPlay();
        setStep(step);
      });
    });

    // Play/Pause toggle handler
    playToggle.addEventListener('click', () => {
      if (isPlaying) {
        stopAutoPlay();
      } else {
        startAutoPlay();
      }
    });

    // Initialize
    setStep(0);
    startAutoPlay();
  </script>
</body>
</html>

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

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

    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      width: 100%;
      max-width: 680px;
    }

    @media (max-width: 520px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }

    .pillar {
      background: #ffffff;
      border: 1.5px solid #e6e6e6;
      border-radius: 12px;
      padding: 14px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      cursor: pointer;
      transition: border-color 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
      user-select: none;
      position: relative;
    }

    .pillar:hover, .pillar.active {
      border-color: #22b7ff;
      box-shadow: 0 4px 12px rgba(34, 183, 255, 0.18);
    }

    .badge {
      width: 28px;
      height: 28px;
      background: #22b7ff;
      color: #ffffff;
      font-weight: 700;
      font-size: 15px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 8px;
      box-shadow: 0 2px 6px rgba(34, 183, 255, 0.35);
    }

    .title {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 8px;
      line-height: 1.2;
    }

    .visual-box {
      width: 100%;
      height: 84px;
      display: flex;
      align-items: center;
      justify-content: center;
      background: #f8fafc;
      border-radius: 8px;
      margin-bottom: 8px;
      position: relative;
      overflow: hidden;
    }

    .subtext {
      font-size: 13px;
      font-weight: 600;
      color: #22b7ff;
      line-height: 1.2;
    }

    /* Visual 1: Organisms */
    .organism-icons {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 26px;
    }

    .organism-icons span {
      transition: transform 0.3s ease;
    }

    .pillar.active .organism-icons span {
      transform: scale(1.1);
    }

    /* Visual 2: Single Cell Unit */
    .cell-unit {
      width: 54px;
      height: 54px;
      border-radius: 50%;
      background: #e0f2fe;
      border: 2px solid #0284c7;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    .cell-nucleus {
      width: 20px;
      height: 20px;
      border-radius: 50%;
      background: #0284c7;
      border: 2px solid #0369a1;
    }

    .metabolism-ring {
      position: absolute;
      inset: -6px;
      border: 2px dashed #38bdf8;
      border-radius: 50%;
      animation: spin 10s linear infinite;
    }

    @keyframes spin {
      100% { transform: rotate(360deg); }
    }

    /* Visual 3: Division */
    .division-anim {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      width: 100%;
    }

    .mini-cell {
      width: 24px;
      height: 24px;
      border-radius: 50%;
      background: #e0f2fe;
      border: 2px solid #0284c7;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .mini-nucleus {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #0284c7;
    }

    .div-arrow {
      color: #22b7ff;
      font-size: 16px;
      font-weight: bold;
    }

    .daughter-pair {
      display: flex;
      gap: 4px;
    }

    .daughter-cell {
      width: 20px;
      height: 20px;
      border-radius: 50%;
      background: #bae6fd;
      border: 1.5px solid #0284c7;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .daughter-nucleus {
      width: 6px;
      height: 6px;
      border-radius: 50%;
      background: #0284c7;
    }

    .pillar.active .mini-cell {
      animation: pulse 1.8s ease-in-out infinite;
    }

    @keyframes pulse {
      0%, 100% { transform: scale(1); }
      50% { transform: scale(1.08); }
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="pillar active" id="pillar1" onclick="setActive(0)">
      <div class="badge">1</div>
      <div class="title">All Organisms</div>
      <div class="visual-box">
        <div class="organism-icons">
          <span title="Bacteria">🦠</span>
          <span title="Plant">🌲</span>
          <span title="Human">👤</span>
        </div>
      </div>
      <div class="subtext">1+ Cells</div>
    </div>

    
    <div class="pillar" id="pillar2" onclick="setActive(1)">
      <div class="badge">2</div>
      <div class="title">Basic Unit</div>
      <div class="visual-box">
        <div class="cell-unit">
          <div class="metabolism-ring"></div>
          <div class="cell-nucleus"></div>
        </div>
      </div>
      <div class="subtext">Structure & Function</div>
    </div>

    
    <div class="pillar" id="pillar3" onclick="setActive(2)">
      <div class="badge">3</div>
      <div class="title">Cells From Cells</div>
      <div class="visual-box">
        <div class="division-anim">
          <div class="mini-cell">
            <div class="mini-nucleus"></div>
          </div>
          <div class="div-arrow">→</div>
          <div class="daughter-pair">
            <div class="daughter-cell"><div class="daughter-nucleus"></div></div>
            <div class="daughter-cell"><div class="daughter-nucleus"></div></div>
          </div>
        </div>
      </div>
      <div class="subtext">Cell Division</div>
    </div>
  </div>

  <script>
    const pillars = [
      document.getElementById('pillar1'),
      document.getElementById('pillar2'),
      document.getElementById('pillar3')
    ];

    let currentIndex = 0;
    let autoInterval = setInterval(nextPillar, 3200);

    function setActive(index) {
      clearInterval(autoInterval);
      currentIndex = index;
      updateClasses();
      autoInterval = setInterval(nextPillar, 3200);
    }

    function nextPillar() {
      currentIndex = (currentIndex + 1) % pillars.length;
      updateClasses();
    }

    function updateClasses() {
      pillars.forEach((p, i) => {
        if (i === currentIndex) {
          p.classList.add('active');
        } else {
          p.classList.remove('active');
        }
      });
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Early Discoveries in Cell Biology</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      background: #f8f9fa;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: auto;
    }

    .cards-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 14px;
      width: 100%;
      max-width: 620px;
      margin: 0 auto;
    }

    @media (max-width: 400px) {
      .cards-grid {
        grid-template-columns: 1fr;
        gap: 12px;
      }
    }

    .discovery-card {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 12px;
      padding: 14px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
    }

    .card-title {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 8px;
      line-height: 1.3;
    }

    .lens-frame {
      width: 130px;
      height: 130px;
      border-radius: 50%;
      position: relative;
      overflow: hidden;
      margin: 4px 0 12px 0;
      box-shadow: inset 0 3px 8px rgba(0,0,0,0.18), 0 2px 5px rgba(0,0,0,0.06);
    }

    .lens-hooke {
      border: 6px solid #b89146;
      background: #dfceb8;
    }

    .lens-leeuwenhoek {
      border: 6px solid #8e9ca8;
      background: radial-gradient(circle at 45% 45%, #e1f5fe 0%, #b3e5fc 65%, #81d4fa 100%);
    }

    .lens-glare {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      border-radius: 50%;
      background: linear-gradient(135deg, rgba(255,255,255,0.45) 0%, rgba(255,255,255,0) 55%);
      pointer-events: none;
    }

    .cork-cells-svg {
      width: 100%;
      height: 100%;
      display: block;
      transform: rotate(-5deg) scale(1.1);
    }

    /* Smooth Microorganism Simulations */
    .organism {
      position: absolute;
      will-change: transform;
    }

    .protozoa {
      width: 28px;
      height: 15px;
      background: #4caf50;
      border-radius: 50%;
      top: 36%;
      left: 32%;
      border: 1.5px solid #2e7d32;
      box-shadow: 0 0 4px rgba(76, 175, 80, 0.35);
      animation: swim1 12s ease-in-out infinite;
    }

    .protozoa::after {
      content: '';
      position: absolute;
      left: -7px;
      top: 5px;
      width: 8px;
      height: 2px;
      background: #2e7d32;
      border-radius: 2px;
      transform-origin: right center;
      animation: flagellum 2.4s ease-in-out infinite alternate;
    }

    .ciliate {
      width: 20px;
      height: 12px;
      background: #00bcd4;
      border-radius: 45%;
      top: 58%;
      left: 56%;
      border: 1.5px dashed #00838f;
      animation: swim2 14s ease-in-out infinite;
    }

    .bacteria {
      width: 12px;
      height: 6px;
      background: #8bc34a;
      border-radius: 4px;
      top: 22%;
      left: 60%;
      animation: drift 9s ease-in-out infinite alternate;
    }

    .spirillum {
      position: absolute;
      top: 68%;
      left: 24%;
      width: 15px;
      height: 4px;
      border-top: 2.5px solid #0288d1;
      border-radius: 50%;
      animation: rotate-wiggle 8s ease-in-out infinite;
    }

    @keyframes swim1 {
      0% { transform: translate(0, 0) rotate(10deg); }
      30% { transform: translate(16px, -12px) rotate(22deg); }
      65% { transform: translate(-10px, 10px) rotate(-12deg); }
      100% { transform: translate(0, 0) rotate(10deg); }
    }

    @keyframes swim2 {
      0% { transform: translate(0, 0) rotate(-20deg); }
      50% { transform: translate(-18px, -14px) rotate(12deg); }
      100% { transform: translate(0, 0) rotate(-20deg); }
    }

    @keyframes drift {
      0% { transform: translate(0, 0) rotate(0deg); }
      50% { transform: translate(-4px, 5px) rotate(15deg); }
      100% { transform: translate(-8px, 10px) rotate(28deg); }
    }

    @keyframes rotate-wiggle {
      0% { transform: rotate(0deg) scale(1); }
      50% { transform: rotate(35deg) scale(1.08); }
      100% { transform: rotate(0deg) scale(1); }
    }

    @keyframes flagellum {
      0% { transform: rotate(-18deg); }
      100% { transform: rotate(18deg); }
    }

    .card-subtitle {
      font-size: 13px;
      font-weight: 600;
      color: #1e2945;
      background: #f1f5f9;
      padding: 6px 10px;
      border-radius: 6px;
      width: 100%;
      line-height: 1.3;
    }
  </style>
</head>
<body>
  <div class="cards-grid">
    
    <div class="discovery-card">
      <div class="card-title">Robert Hooke • 1665</div>
      <div class="lens-frame lens-hooke" title="Grid of non-living cork cell walls">
        <svg class="cork-cells-svg" viewBox="0 0 100 100" aria-label="Cork cells under microscope">
          <defs>
            <pattern id="corkPattern" width="16" height="12" patternUnits="userSpaceOnUse">
              <rect x="1" y="1" width="14" height="10" rx="1.5" fill="#d7c4a7" stroke="#7a4f2d" stroke-width="1.5"/>
              <rect x="9" y="-5" width="14" height="10" rx="1.5" fill="#d7c4a7" stroke="#7a4f2d" stroke-width="1.5"/>
              <rect x="9" y="7" width="14" height="10" rx="1.5" fill="#d7c4a7" stroke="#7a4f2d" stroke-width="1.5"/>
            </pattern>
          </defs>
          <rect width="100" height="100" fill="url(#corkPattern)" />
        </svg>
        <div class="lens-glare"></div>
      </div>
      <div class="card-subtitle">First named cells (cork)</div>
    </div>

    
    <div class="discovery-card">
      <div class="card-title">Anton van Leeuwenhoek • 1674</div>
      <div class="lens-frame lens-leeuwenhoek" title="Active living microorganisms in water">
        <div class="organism protozoa" title="Protozoan"></div>
        <div class="organism ciliate" title="Ciliate"></div>
        <div class="organism bacteria" title="Bacterium"></div>
        <div class="organism spirillum" title="Spirillum"></div>
        <div class="lens-glare"></div>
      </div>
      <div class="card-subtitle">First observed living single cells</div>
    </div>
  </div>
</body>
</html>

OGS.7.LS.1

Aligned learning resources

Related diagrams