<!DOCTYPE html>
<html lang="en">
<head>
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  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Mechanism of Oxygenic Photosynthesis</title>
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          <text x="502" y="176" text-anchor="middle" font-size="12" font-weight="700" fill="#ccfbf1">(Calvin Cycle)</text>
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            Net: 2H₂O + CO₂ + Light ➔ (CH₂O)ₙ + O₂
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      <button class="step-btn" data-step="1">2. Water Splitting &amp; O₂</button>
      <button class="step-btn" data-step="2">3. Carbon Fixation</button>
      <button class="step-btn" data-step="3">4. Complete Reaction</button>
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Evolution of Earth's Atmosphere and the Great Oxidation Event

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Marine Iron Sink Buffer</title>
  <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: #0f172a;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 6px;
      user-select: none;
      width: 100%;
      min-height: 100%;
    }

    /* Interactive Stepper & Controls */
    .controls {
      display: flex;
      gap: 8px;
      margin-bottom: 8px;
      width: 100%;
      max-width: 620px;
    }

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      flex: 1;
      padding: 8px 10px;
      font-size: 13px;
      font-weight: 600;
      border: 1.5px solid #cbd5e1;
      border-radius: 6px;
      background: #ffffff;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
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      min-height: 38px;
      text-align: center;
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      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 18px;
      height: 18px;
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      color: #334155;
      font-size: 11px;
      font-weight: 700;
    }

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      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 5px rgba(2, 132, 199, 0.3);
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      background: #ffffff;
      color: #0284c7;
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      max-width: 620px;
      position: relative;
      display: flex;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: hidden;
      border-radius: 6px;
    }

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      font-size: 13px;
      font-weight: 700;
      fill: #ffffff;
      letter-spacing: 0.02em;
    }

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      font-size: 12px;
      font-weight: 600;
      fill: #ffffff;
    }

    .ion-label {
      font-size: 13px;
      font-weight: 800;
      fill: #bae6fd;
      letter-spacing: 0.03em;
    }

    /* Particle Animations */
    .bubble {
      animation: floatUp 3s infinite linear;
    }

    .precipitate {
      animation: sinkDown 3.2s infinite linear;
    }

    @keyframes floatUp {
      0% { transform: translateY(0); opacity: 0.2; }
      20% { opacity: 0.95; }
      80% { opacity: 0.95; }
      100% { transform: translateY(-75px); opacity: 0; }
    }

    @keyframes sinkDown {
      0% { transform: translateY(0); opacity: 0.2; }
      25% { opacity: 1; }
      80% { opacity: 1; }
      100% { transform: translateY(68px); opacity: 0; }
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      transition: opacity 0.35s ease;
    }

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      opacity: 0;
      pointer-events: none;
    }

    .visible {
      opacity: 1;
      pointer-events: auto;
    }

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      .btn-step {
        font-size: 11.5px;
        padding: 6px 6px;
      }
    }
  </style>
</head>
<body>

  
  <div class="controls" role="tablist" aria-label="Marine Iron Sink Stages">
    <button id="btn1" class="btn-step active" onclick="setStep(1)" role="tab" aria-selected="true">
      <span class="step-num">1</span> Iron Sink Active
    </button>
    <button id="btn2" class="btn-step" onclick="setStep(2)" role="tab" aria-selected="false">
      <span class="step-num">2</span> Sink Saturated (O₂ Escapes)
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      </defs>

      
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        <text id="gaugeText" x="72" y="55" class="badge-label" text-anchor="middle" font-size="11" fill="#facc15">Buffering Fe²⁺</text>
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        <rect x="14" y="44" width="140" height="24" rx="4" fill="#0f172ad9" stroke="#64748b" stroke-width="1"/>
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          <rect x="190" y="128" width="46" height="22" rx="4" fill="#0f172a80"/>
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          <text x="102" y="21" class="badge-label" text-anchor="middle" fill="#fca5a5" font-size="12.5">4Fe²⁺ + 3O₂ → 2Fe₂O₃ ↓</text>
        </g>

        
        <g class="precipitate" style="animation-duration: 3.2s;">
          <circle cx="235" cy="225" r="5" fill="#ef4444" stroke="#7f1d1d" stroke-width="1"/>
          <circle cx="285" cy="220" r="5.5" fill="#dc2626" stroke="#7f1d1d" stroke-width="1"/>
          <circle cx="345" cy="228" r="4.5" fill="#b91c1c" stroke="#7f1d1d" stroke-width="1"/>
        </g>
        <g class="precipitate" style="animation-duration: 3.6s; animation-delay: 1.3s;">
          <circle cx="255" cy="215" r="4.5" fill="#ef4444" stroke="#7f1d1d" stroke-width="1"/>
          <circle cx="315" cy="210" r="5" fill="#dc2626" stroke="#7f1d1d" stroke-width="1"/>
          <circle cx="375" cy="218" r="5" fill="#b91c1c" stroke="#7f1d1d" stroke-width="1"/>
        </g>

        <text x="325" y="260" class="badge-label" fill="#fca5a5" font-size="11.5" opacity="0.95">Insoluble Fe₂O₃ settles</text>
      </g>

      
      <g id="stage2Group" class="state-layer hidden">
        
        <rect x="14" y="44" width="165" height="26" rx="4" fill="#0284c7" stroke="#ffffff" stroke-width="1.2" filter="url(#shadow)"/>
        <text x="96" y="61" class="main-label" text-anchor="middle" fill="#ffffff" font-size="12">O₂ Accumulates in Air</text>

        
        <g stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" fill="none" opacity="0.95">
          <path d="M 85 240 L 85 65" stroke-dasharray="6 4"/>
          <polyline points="78,75 85,63 92,75"/>
          
          <path d="M 160 230 L 160 55" stroke-dasharray="6 4"/>
          <polyline points="153,65 160,53 167,65"/>

          <path d="M 240 220 L 240 65" stroke-dasharray="6 4"/>
          <polyline points="233,75 240,63 247,75"/>
        </g>

        
        <g transform="translate(265, 42)">
          <circle cx="0" cy="0" r="14" fill="#ffffff" stroke="#0284c7" stroke-width="2" filter="url(#shadow)"/>
          <text x="0" y="5" class="main-label" text-anchor="middle" fill="#0284c7" font-size="12">O₂</text>
        </g>
        <g transform="translate(325, 30)">
          <circle cx="0" cy="0" r="13" fill="#ffffff" stroke="#0284c7" stroke-width="2" filter="url(#shadow)"/>
          <text x="0" y="4.5" class="main-label" text-anchor="middle" fill="#0284c7" font-size="11.5">O₂</text>
        </g>
        <g transform="translate(385, 45)">
          <circle cx="0" cy="0" r="13" fill="#ffffff" stroke="#0284c7" stroke-width="2" filter="url(#shadow)"/>
          <text x="0" y="4.5" class="main-label" text-anchor="middle" fill="#0284c7" font-size="11.5">O₂</text>
        </g>

        
        <rect x="230" y="145" width="220" height="32" rx="6" fill="#0f172af0" stroke="#e2e8f0" stroke-width="1.2" filter="url(#shadow)"/>
        <text x="340" y="166" class="main-label" text-anchor="middle" fill="#f8fafc" font-size="12.5">Fe²⁺ Exhausted — Sink Saturated</text>

        <rect x="235" y="190" width="210" height="24" rx="4" fill="#0369a1cc"/>
        <text x="340" y="206" class="badge-label" text-anchor="middle" fill="#e0f2fe" font-size="11.5">Unbound O₂ outgasses into sky</text>
      </g>
    </svg>
  </div>

  <script>
    function setStep(step) {
      const b1 = document.getElementById('btn1');
      const b2 = document.getElementById('btn2');
      const s1 = document.getElementById('stage1Group');
      const s2 = document.getElementById('stage2Group');
      const sky = document.getElementById('skyBg');
      const gaugeFill = document.getElementById('gaugeFill');
      const gaugeText = document.getElementById('gaugeText');

      if (step === 1) {
        b1.classList.add('active');
        b1.setAttribute('aria-selected', 'true');
        b2.classList.remove('active');
        b2.setAttribute('aria-selected', 'false');

        s1.classList.remove('hidden');
        s1.classList.add('visible');
        s2.classList.remove('visible');
        s2.classList.add('hidden');
        
        sky.setAttribute('fill', 'url(#skyStage1)');
        gaugeFill.setAttribute('width', '58');
        gaugeFill.setAttribute('fill', 'url(#gaugeGrad)');
        gaugeText.textContent = 'Buffering Fe²⁺';
        gaugeText.setAttribute('fill', '#facc15');
      } else {
        b2.classList.add('active');
        b2.setAttribute('aria-selected', 'true');
        b1.classList.remove('active');
        b1.setAttribute('aria-selected', 'false');

        s2.classList.remove('hidden');
        s2.classList.add('visible');
        s1.classList.remove('visible');
        s1.classList.add('hidden');

        sky.setAttribute('fill', 'url(#skyStage2)');
        gaugeFill.setAttribute('width', '117');
        gaugeFill.setAttribute('fill', '#ef4444');
        gaugeText.textContent = '100% Full';
        gaugeText.setAttribute('fill', '#fca5a5');
      }
    }
  </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, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .nav-toggle {
      display: flex;
      gap: 6px;
      justify-content: center;
    }

    .tab-btn {
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      border: 1px solid #d1d5db;
      background: #f8fafc;
      border-radius: 20px;
      cursor: pointer;
      color: #4b5563;
      transition: background 0.2s, color 0.2s, border-color 0.2s;
    }

    .tab-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }

    .panels {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
    }

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

    .panel-box {
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px;
      background: #f8fafc;
      display: flex;
      flex-direction: column;
      gap: 4px;
      transition: opacity 0.25s, box-shadow 0.25s;
    }

    .panel-box.dimmed {
      opacity: 0.4;
    }

    .panel-box.highlight {
      box-shadow: 0 0 0 2px #0284c7;
      background: #ffffff;
    }

    .panel-title {
      font-size: 13px;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .tag {
      font-size: 11px;
      font-weight: 600;
      padding: 2px 6px;
      border-radius: 4px;
    }

    .tag-pre { background: #fee2e2; color: #b91c1c; }
    .tag-post { background: #dcfce7; color: #15803d; }

    .sky-svg {
      width: 100%;
      height: 105px;
      border-radius: 6px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
    }

    .graph-container {
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      background: #ffffff;
      padding: 6px 8px;
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .graph-header {
      display: flex;
      justify-content: space-between;
      align-items: baseline;
      font-size: 12px;
      font-weight: 700;
      color: #334155;
    }

    .graph-svg {
      width: 100%;
      height: 120px;
    }

    .axis-label {
      font-size: 10px;
      fill: #64748b;
      font-family: inherit;
    }

    .goe-marker {
      stroke: #dc2626;
      stroke-dasharray: 3, 3;
      stroke-width: 1.5;
    }
  </style>
</head>
<body>

  <div class="nav-toggle">
    <button class="tab-btn active" id="btnAll" onclick="setMode('all')">Compare Both</button>
    <button class="tab-btn" id="btnPre" onclick="setMode('pre')">&lt; 2.4 Ga (Pre-GOE)</button>
    <button class="tab-btn" id="btnPost" onclick="setMode('post')">&gt; 2.4 Ga (Post-GOE)</button>
  </div>

  <div class="panels">
    
    <div class="panel-box" id="boxPre">
      <div class="panel-title">
        <span>Pre-GOE Atmosphere</span>
        <span class="tag tag-pre">&lt; 2.4 Ga</span>
      </div>
      <svg class="sky-svg" viewBox="0 0 240 105">
        
        <circle cx="28" cy="18" r="12" fill="#f59e0b" />
        <path d="M 32 30 L 70 65" stroke="#8b5cf6" stroke-width="2" stroke-dasharray="3,2" />
        <path d="M 40 24 L 140 68" stroke="#8b5cf6" stroke-width="2" stroke-dasharray="3,2" />
        <path d="M 42 16 L 205 65" stroke="#8b5cf6" stroke-width="2" stroke-dasharray="3,2" />
        <text x="68" y="24" fill="#7c3aed" font-size="10" font-weight="700">Solar UV Penetrates</text>

        
        <rect x="75" y="44" width="90" height="22" rx="4" fill="#fef3c7" stroke="#f59e0b" stroke-width="1"/>
        <text x="120" y="59" text-anchor="middle" font-size="11" font-weight="700" fill="#92400e">SO₂ + UV → Δ³³S</text>

        
        <rect x="0" y="80" width="240" height="25" fill="#e2e8f0" />
        <line x1="0" y1="80" x2="240" y2="80" stroke="#94a3b8" stroke-width="1.5" />
        <text x="120" y="96" text-anchor="middle" font-size="11" font-weight="700" fill="#b91c1c">Large MIF-S (Δ³³S ≠ 0)</text>
      </svg>
    </div>

    
    <div class="panel-box" id="boxPost">
      <div class="panel-title">
        <span>Post-GOE Atmosphere</span>
        <span class="tag tag-post">&gt; 2.4 Ga</span>
      </div>
      <svg class="sky-svg" viewBox="0 0 240 105">
        
        <circle cx="28" cy="18" r="12" fill="#f59e0b" />

        
        <rect x="20" y="36" width="200" height="18" rx="9" fill="#bae6fd" stroke="#0284c7" stroke-width="1.5" />
        <text x="120" y="49" text-anchor="middle" font-size="10.5" font-weight="700" fill="#0369a1">Ozone Shield (O₃) Blocks UV</text>

        
        <path d="M 32 30 L 45 36" stroke="#8b5cf6" stroke-width="2" />
        <path d="M 40 24 L 75 36" stroke="#8b5cf6" stroke-width="2" />
        <path d="M 42 16 L 110 36" stroke="#8b5cf6" stroke-width="2" />

        
        <text x="120" y="70" text-anchor="middle" font-size="10" fill="#64748b">No SO₂ Photolysis</text>

        
        <rect x="0" y="80" width="240" height="25" fill="#e2e8f0" />
        <line x1="0" y1="80" x2="240" y2="80" stroke="#94a3b8" stroke-width="1.5" />
        <text x="120" y="96" text-anchor="middle" font-size="11" font-weight="700" fill="#15803d">Zero MIF-S (Δ³³S = 0)</text>
      </svg>
    </div>
  </div>

  
  <div class="graph-container">
    <div class="graph-header">
      <span>Geological Rock Record (Δ³³S vs. Age)</span>
      <span style="font-size:11px; color:#64748b;">MIF-S Signal</span>
    </div>
    <svg class="graph-svg" id="graphSvg" viewBox="0 0 440 120"></svg>
  </div>

  <script>
    // Exact coordinate mapping for sulfur fractionation scatter plot
    const svg = document.getElementById('graphSvg');
    const xMin = 3.8, xMax = 1.0; // Ga (billion years ago)
    const yMin = -4, yMax = 8;    // Δ33S (permil)

    const padL = 40, padR = 20, padT = 15, padB = 25;
    const w = 440 - padL - padR;
    const h = 120 - padT - padB;

    function toSvgX(ga) {
      return padL + ((xMin - ga) / (xMin - xMax)) * w;
    }

    function toSvgY(val) {
      return padT + ((yMax - val) / (yMax - yMin)) * h;
    }

    // Generate accurate geological data points
    const prePoints = [
      {x: 3.8, y: 0.5}, {x: 3.6, y: -1.2}, {x: 3.5, y: 2.1}, {x: 3.4, y: 1.8},
      {x: 3.2, y: -2.3}, {x: 3.0, y: 4.8}, {x: 2.9, y: 3.2}, {x: 2.8, y: -1.8},
      {x: 2.7, y: 7.4}, {x: 2.65, y: -3.2}, {x: 2.6, y: 5.1}, {x: 2.55, y: 2.3},
      {x: 2.5, y: -2.1}, {x: 2.45, y: 4.2}, {x: 2.42, y: -1.5}
    ];

    const postPoints = [
      {x: 2.35, y: 0.05}, {x: 2.3, y: -0.08}, {x: 2.2, y: 0.02}, {x: 2.1, y: 0.0},
      {x: 2.0, y: -0.05}, {x: 1.9, y: 0.04}, {x: 1.8, y: -0.02}, {x: 1.6, y: 0.01},
      {x: 1.4, y: 0.0}, {x: 1.2, y: -0.03}, {x: 1.0, y: 0.02}
    ];

    function drawGraph() {
      const yZero = toSvgY(0);
      const xGoe = toSvgX(2.4);

      let html = `
        
        <line x1="${padL}" y1="${toSvgY(yMin)}" x2="${padL + w}" y2="${toSvgY(yMin)}" stroke="#cbd5e1" stroke-width="1"/>
        <line x1="${padL}" y1="${padT}" x2="${padL}" y2="${padT + h}" stroke="#cbd5e1" stroke-width="1"/>
        <line x1="${padL}" y1="${yZero}" x2="${padL + w}" y2="${yZero}" stroke="#94a3b8" stroke-dasharray="2,2" stroke-width="1"/>

        
        <text x="${padL - 6}" y="${toSvgY(6)}" text-anchor="end" class="axis-label">+6‰</text>
        <text x="${padL - 6}" y="${yZero + 3}" text-anchor="end" class="axis-label" font-weight="700">0‰</text>
        <text x="${padL - 6}" y="${toSvgY(-3)}" text-anchor="end" class="axis-label">-3‰</text>

        
        <text x="${toSvgX(3.8)}" y="${padT + h + 16}" text-anchor="middle" class="axis-label">3.8 Ga</text>
        <text x="${toSvgX(3.0)}" y="${padT + h + 16}" text-anchor="middle" class="axis-label">3.0 Ga</text>
        <text x="${toSvgX(2.4)}" y="${padT + h + 16}" text-anchor="middle" class="axis-label" fill="#dc2626" font-weight="700">2.4 Ga (GOE)</text>
        <text x="${toSvgX(1.5)}" y="${padT + h + 16}" text-anchor="middle" class="axis-label">1.5 Ga</text>

        
        <line x1="${xGoe}" y1="${padT}" x2="${xGoe}" y2="${padT + h}" class="goe-marker"/>
      `;

      // Draw Pre-GOE Points
      prePoints.forEach(p => {
        html += `<circle class="pt-pre" cx="${toSvgX(p.x)}" cy="${toSvgY(p.y)}" r="3.5" fill="#dc2626" opacity="0.8"/>`;
      });

      // Draw Post-GOE Points
      postPoints.forEach(p => {
        html += `<circle class="pt-post" cx="${toSvgX(p.x)}" cy="${toSvgY(p.y)}" r="3.5" fill="#16a34a" opacity="0.8"/>`;
      });

      svg.innerHTML = html;
    }

    function setMode(mode) {
      document.getElementById('btnAll').classList.toggle('active', mode === 'all');
      document.getElementById('btnPre').classList.toggle('active', mode === 'pre');
      document.getElementById('btnPost').classList.toggle('active', mode === 'post');

      const bPre = document.getElementById('boxPre');
      const bPost = document.getElementById('boxPost');

      if (mode === 'all') {
        bPre.classList.remove('dimmed', 'highlight');
        bPost.classList.remove('dimmed', 'highlight');
        document.querySelectorAll('.pt-pre').forEach(el => el.style.opacity = '0.85');
        document.querySelectorAll('.pt-post').forEach(el => el.style.opacity = '0.85');
      } else if (mode === 'pre') {
        bPre.classList.remove('dimmed');
        bPre.classList.add('highlight');
        bPost.classList.add('dimmed');
        bPost.classList.remove('highlight');
        document.querySelectorAll('.pt-pre').forEach(el => el.style.opacity = '1');
        document.querySelectorAll('.pt-post').forEach(el => el.style.opacity = '0.15');
      } else if (mode === 'post') {
        bPost.classList.remove('dimmed');
        bPost.classList.add('highlight');
        bPre.classList.add('dimmed');
        bPre.classList.remove('highlight');
        document.querySelectorAll('.pt-pre').forEach(el => el.style.opacity = '0.15');
        document.querySelectorAll('.pt-post').forEach(el => el.style.opacity = '1');
      }
    }

    drawGraph();
  </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>Earth's Early Atmosphere Transition</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      width: 100%;
      min-height: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 8px;
    }

    .diagram-wrap {
      width: 100%;
      max-width: 620px;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    /* Tab switcher */
    .nav-bar {
      display: flex;
      background: #e2e8f0;
      padding: 3px;
      border-radius: 10px;
      gap: 4px;
    }
    .tab-btn {
      flex: 1;
      padding: 7px 10px;
      font-size: 12px;
      font-weight: 600;
      border: none;
      background: transparent;
      color: #64748b;
      border-radius: 7px;
      cursor: pointer;
      transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
      text-align: center;
      white-space: nowrap;
    }
    .tab-btn.active {
      background: #ffffff;
      color: #0f172a;
      box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    }

    /* Stage canvas */
    .stage-box {
      width: 100%;
      background: #090d16;
      border-radius: 12px;
      position: relative;
      overflow: hidden;
      aspect-ratio: 2 / 1;
      min-height: 240px;
      max-height: 320px;
      border: 1px solid #334155;
    }

    .scene-svg {
      width: 100%;
      height: 100%;
      display: block;
      transition: viewBox 0.4s ease;
    }

    /* Gas pill legend */
    .legend-row {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
      justify-content: center;
      align-items: center;
      padding: 4px 0;
    }
    .gas-tag {
      font-weight: 700;
      font-size: 11px;
      padding: 3px 8px;
      border-radius: 999px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      border: 1.5px solid transparent;
      user-select: none;
    }
    .tag-h-he { background: #f8fafc; color: #0f172a; border-color: #94a3b8; }
    .tag-co2 { background: #fff7ed; color: #c2410c; border-color: #f97316; }
    .tag-h2o { background: #ecfeff; color: #0e7490; border-color: #06b6d4; }
    .tag-n2 { background: #f5f3ff; color: #6d28d9; border-color: #8b5cf6; }
    .tag-so2 { background: #fefce8; color: #a16207; border-color: #eab308; }

    /* Timeline component */
    .timeline {
      display: flex;
      align-items: center;
      justify-content: space-between;
      position: relative;
      padding: 8px 12px;
      background: #ffffff;
      border-radius: 10px;
      border: 1px solid #e2e8f0;
      gap: 8px;
    }
    .timeline-line {
      position: absolute;
      left: 100px;
      right: 100px;
      top: 50%;
      height: 3px;
      background: linear-gradient(90deg, #38bdf8, #f97316 50%, #a855f7);
      transform: translateY(-50%);
      z-index: 1;
      border-radius: 2px;
    }
    .t-node {
      position: relative;
      z-index: 2;
      background: #ffffff;
      padding: 5px 10px;
      border-radius: 8px;
      border: 1.5px solid #cbd5e1;
      text-align: center;
      cursor: pointer;
      transition: border-color 0.2s ease, box-shadow 0.2s ease;
      min-width: 100px;
    }
    .t-node:hover {
      border-color: #0284c7;
      box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.15);
    }
    .t-node.active-node {
      border-color: #0284c7;
      background: #f0f9ff;
      box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.25);
    }
    .t-time { font-size: 12px; font-weight: 800; color: #0f172a; }
    .t-name { font-size: 10px; color: #64748b; font-weight: 600; }

    /* Smooth gas animations without flickering */
    @keyframes smoothEscape1 {
      0% { transform: translate(0, 0); opacity: 0; }
      15% { opacity: 1; }
      80% { opacity: 0.9; }
      100% { transform: translate(16px, -24px); opacity: 0; }
    }
    @keyframes smoothEscape2 {
      0% { transform: translate(0, 0); opacity: 0; }
      15% { opacity: 1; }
      80% { opacity: 0.9; }
      100% { transform: translate(22px, -30px); opacity: 0; }
    }
    @keyframes smoothPuff {
      0% { transform: translateY(0); opacity: 0; }
      20% { opacity: 1; }
      80% { opacity: 0.95; }
      100% { transform: translateY(-26px); opacity: 0; }
    }
    @keyframes pulseSun {
      0%, 100% { opacity: 0.75; }
      50% { opacity: 1; }
    }

    .esc-p1 { animation: smoothEscape1 5.5s infinite cubic-bezier(0.4, 0, 0.2, 1); }
    .esc-p2 { animation: smoothEscape2 6.2s infinite cubic-bezier(0.4, 0, 0.2, 1); }
    .volcano-puff1 { animation: smoothPuff 5.2s infinite cubic-bezier(0.4, 0, 0.2, 1); }
    .volcano-puff2 { animation: smoothPuff 5.8s infinite cubic-bezier(0.4, 0, 0.2, 1); }
    .solar-glow { animation: pulseSun 4s infinite ease-in-out; }

    @media (max-width: 480px) {
      .timeline {
        flex-direction: column;
        gap: 8px;
      }
      .timeline-line {
        display: none;
      }
      .t-node {
        width: 100%;
      }
      .tab-btn {
        font-size: 11px;
        padding: 6px 4px;
      }
      .stage-box {
        aspect-ratio: 16 / 10;
        min-height: 220px;
      }
    }
  </style>
</head>
<body>

  <div class="diagram-wrap">
    
    
    <div class="nav-bar">
      <button class="tab-btn active" id="btnBoth" onclick="setView('both')">Side-by-Side View</button>
      <button class="tab-btn" id="btnPrim" onclick="setView('primordial')">~4.5 Ga Primordial</button>
      <button class="tab-btn" id="btnSec" onclick="setView('secondary')">~4.0 Ga Secondary</button>
    </div>

    
    <div class="stage-box">
      <svg class="scene-svg" viewBox="0 0 600 280" id="mainSvg">
        <defs>
          <radialGradient id="magmaEarth" cx="40%" cy="35%" r="65%">
            <stop offset="0%" stop-color="#fdba74" />
            <stop offset="45%" stop-color="#ea580c" />
            <stop offset="85%" stop-color="#9a3412" />
            <stop offset="100%" stop-color="#431407" />
          </radialGradient>
          <radialGradient id="coolingEarth" cx="45%" cy="35%" r="65%">
            <stop offset="0%" stop-color="#64748b" />
            <stop offset="50%" stop-color="#334155" />
            <stop offset="85%" stop-color="#1e293b" />
            <stop offset="100%" stop-color="#0f172a" />
          </radialGradient>
          <linearGradient id="solarRay" x1="0%" y1="0%" x2="100%" y2="100%">
            <stop offset="0%" stop-color="#fde047" stop-opacity="1" />
            <stop offset="100%" stop-color="#f59e0b" stop-opacity="0.1" />
          </linearGradient>
        </defs>

        
        <g id="panelLeft">
          
          <rect x="0" y="0" width="300" height="280" fill="#0b1120" />
          
          
          <g class="solar-glow">
            <circle cx="24" cy="24" r="36" fill="#fbbf24" opacity="0.2" />
            <circle cx="24" cy="24" r="18" fill="#fef08a" />
            <line x1="42" y1="40" x2="120" y2="100" stroke="url(#solarRay)" stroke-width="3" stroke-linecap="round" stroke-dasharray="5,4" />
            <line x1="48" y1="24" x2="135" y2="48" stroke="url(#solarRay)" stroke-width="2.5" stroke-dasharray="5,4" />
            <line x1="24" y1="48" x2="72" y2="132" stroke="url(#solarRay)" stroke-width="2.5" stroke-dasharray="5,4" />
            <text x="56" y="24" fill="#fde047" font-size="10" font-weight="800" letter-spacing="0.5">SOLAR WIND</text>
          </g>

          
          <g transform="translate(100, 200)">
            <circle cx="0" cy="0" r="68" fill="url(#magmaEarth)" stroke="#f97316" stroke-width="1.5" />
            
            <path d="M-45,-20 Q-15,-10 -5,-35 Q15,-20 45,-15" fill="none" stroke="#fef08a" stroke-width="2" opacity="0.85" />
            <path d="M-35,15 Q0,5 28,25 Q48,10 55,-5" fill="none" stroke="#fde047" stroke-width="2" opacity="0.8" />
          </g>

          
          <path d="M 85,145 Q 65,95 45,70" fill="none" stroke="#60a5fa" stroke-width="1.5" stroke-dasharray="3,3" opacity="0.8" />
          <polygon points="43,67 52,70 47,77" fill="#60a5fa" />

          <path d="M 135,140 Q 165,85 195,50" fill="none" stroke="#60a5fa" stroke-width="1.5" stroke-dasharray="3,3" opacity="0.8" />
          <polygon points="196,48 187,52 193,59" fill="#60a5fa" />

          
          <g class="esc-p1" style="animation-delay: 0s;">
            <g transform="translate(62, 95)">
              <rect x="-18" y="-11" width="36" height="22" rx="11" fill="#f8fafc" stroke="#38bdf8" stroke-width="1.8" />
              <text x="0" y="5" fill="#0f172a" font-size="12" font-weight="800" text-anchor="middle">H₂</text>
            </g>
          </g>

          <g class="esc-p2" style="animation-delay: 1.5s;">
            <g transform="translate(162, 85)">
              <rect x="-18" y="-11" width="36" height="22" rx="11" fill="#f8fafc" stroke="#94a3b8" stroke-width="1.8" />
              <text x="0" y="5" fill="#0f172a" font-size="12" font-weight="800" text-anchor="middle">He</text>
            </g>
          </g>

          <g class="esc-p1" style="animation-delay: 3s;">
            <g transform="translate(125, 55)">
              <rect x="-18" y="-11" width="36" height="22" rx="11" fill="#f8fafc" stroke="#38bdf8" stroke-width="1.8" />
              <text x="0" y="5" fill="#0f172a" font-size="12" font-weight="800" text-anchor="middle">H₂</text>
            </g>
          </g>

          
          <rect x="12" y="244" width="180" height="24" rx="6" fill="#0f172a" stroke="#334155" stroke-width="1.2" />
          <text x="102" y="260" fill="#f8fafc" font-size="11" font-weight="700" text-anchor="middle">PRIMORDIAL: ESCAPING</text>
        </g>

        
        <line x1="300" y1="0" x2="300" y2="280" stroke="#334155" stroke-width="2" stroke-dasharray="5,5" id="splitLine" />

        
        <g id="panelRight">
          
          <rect x="300" y="0" width="300" height="280" fill="#0f172a" />

          
          <g transform="translate(450, 205)">
            
            <circle cx="0" cy="0" r="68" fill="url(#coolingEarth)" stroke="#475569" stroke-width="1.5" />
            
            
            <polygon points="-44,-46 -26,-15 -62,-15" fill="#1e293b" stroke="#64748b" stroke-width="1.2" />
            <polygon points="-44,-46 -37,-34 -51,-34" fill="#ea580c" />
            
            
            <polygon points="24,-50 42,-15 6,-15" fill="#1e293b" stroke="#64748b" stroke-width="1.2" />
            <polygon points="24,-50 30,-38 18,-38" fill="#ea580c" />

            
            <ellipse cx="-6" cy="-2" rx="18" ry="5" fill="#c2410c" opacity="0.9" />
          </g>

          
          <g class="volcano-puff1" style="animation-delay: 0s;">
            
            <g transform="translate(385, 115)">
              <rect x="-20" y="-11" width="40" height="22" rx="11" fill="#ecfeff" stroke="#06b6d4" stroke-width="1.8" />
              <text x="0" y="5" fill="#0891b2" font-size="12" font-weight="800" text-anchor="middle">H₂O</text>
            </g>
          </g>

          <g class="volcano-puff2" style="animation-delay: 1.2s;">
            
            <g transform="translate(470, 95)">
              <rect x="-20" y="-11" width="40" height="22" rx="11" fill="#fff7ed" stroke="#f97316" stroke-width="1.8" />
              <text x="0" y="5" fill="#ea580c" font-size="12" font-weight="800" text-anchor="middle">CO₂</text>
            </g>
          </g>

          <g class="volcano-puff1" style="animation-delay: 2.4s;">
            
            <g transform="translate(425, 55)">
              <rect x="-18" y="-11" width="36" height="22" rx="11" fill="#f5f3ff" stroke="#8b5cf6" stroke-width="1.8" />
              <text x="0" y="5" fill="#7c3aed" font-size="12" font-weight="800" text-anchor="middle">N₂</text>
            </g>
          </g>

          <g class="volcano-puff2" style="animation-delay: 3.6s;">
            
            <g transform="translate(525, 125)">
              <rect x="-18" y="-10" width="36" height="20" rx="10" fill="#fefce8" stroke="#eab308" stroke-width="1.8" />
              <text x="0" y="4.5" fill="#ca8a04" font-size="11" font-weight="800" text-anchor="middle">SO₂</text>
            </g>
            <g transform="translate(535, 70)">
              <rect x="-18" y="-10" width="36" height="20" rx="10" fill="#f8fafc" stroke="#94a3b8" stroke-width="1.5" />
              <text x="0" y="4.5" fill="#334155" font-size="10" font-weight="800" text-anchor="middle">CH₄</text>
            </g>
          </g>

          
          <rect x="312" y="244" width="190" height="24" rx="6" fill="#0f172a" stroke="#334155" stroke-width="1.2" />
          <text x="407" y="260" fill="#f8fafc" font-size="11" font-weight="700" text-anchor="middle">SECONDARY: OUTGASSING</text>
        </g>
      </svg>
    </div>

    
    <div class="legend-row">
      <span class="gas-tag tag-h-he">H₂ / He (Light Gases)</span>
      <span class="gas-tag tag-co2">CO₂ (Carbon Dioxide)</span>
      <span class="gas-tag tag-h2o">H₂O (Water Vapor)</span>
      <span class="gas-tag tag-n2">N₂ (Nitrogen)</span>
      <span class="gas-tag tag-so2">SO₂ (Sulfur Dioxide)</span>
    </div>

    
    <div class="timeline">
      <div class="timeline-line"></div>
      
      <div class="t-node active-node" id="nodePrim" onclick="setView('primordial')">
        <div class="t-time">~4.5 Ga</div>
        <div class="t-name">Primordial (Lost)</div>
      </div>

      <div style="font-size: 11px; font-weight: 600; color: #64748b; z-index: 2; background: #ffffff; padding: 2px 6px; border-radius: 4px;">
        Atmospheric Evolution
      </div>

      <div class="t-node active-node" id="nodeSec" onclick="setView('secondary')">
        <div class="t-time">~4.0 Ga</div>
        <div class="t-name">Secondary (Volcanic)</div>
      </div>
    </div>

  </div>

  <script>
    function setView(mode) {
      const svg = document.getElementById('mainSvg');
      const split = document.getElementById('splitLine');
      const btnBoth = document.getElementById('btnBoth');
      const btnPrim = document.getElementById('btnPrim');
      const btnSec = document.getElementById('btnSec');
      const nodePrim = document.getElementById('nodePrim');
      const nodeSec = document.getElementById('nodeSec');

      // Reset tabs & timeline nodes
      [btnBoth, btnPrim, btnSec].forEach(b => b.classList.remove('active'));
      [nodePrim, nodeSec].forEach(n => n.classList.remove('active-node'));

      if (mode === 'primordial') {
        btnPrim.classList.add('active');
        nodePrim.classList.add('active-node');
        split.style.display = 'none';
        svg.setAttribute('viewBox', '0 0 300 280');
      } else if (mode === 'secondary') {
        btnSec.classList.add('active');
        nodeSec.classList.add('active-node');
        split.style.display = 'none';
        svg.setAttribute('viewBox', '300 0 300 280');
      } else {
        btnBoth.classList.add('active');
        nodePrim.classList.add('active-node');
        nodeSec.classList.add('active-node');
        split.style.display = 'block';
        svg.setAttribute('viewBox', '0 0 600 280');
      }
    }
  </script>
</body>
</html>

OGS.11.ESS.4

Aligned learning resources

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