<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Ribosome Translation Elongation</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      width: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #0f172a;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 8px;
      user-select: none;
    }

    .main-wrap {
      width: 100%;
      max-width: 640px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    /* Controls Header */
    .controls {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 6px;
      width: 100%;
    }

    .step-buttons {
      display: flex;
      gap: 6px;
      flex: 1;
    }

    .step-btn {
      flex: 1;
      padding: 7px 4px;
      font-size: 12px;
      font-weight: 700;
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 6px;
      color: #334155;
      cursor: pointer;
      text-align: center;
      transition: background-color 0.2s, color 0.2s, border-color 0.2s;
    }
    .step-btn:hover {
      background-color: #f1f5f9;
      border-color: #94a3b8;
    }
    .step-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }

    .play-btn {
      padding: 7px 12px;
      font-size: 12px;
      font-weight: 700;
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 6px;
      color: #0f172a;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      min-width: 72px;
      transition: background-color 0.2s;
    }
    .play-btn:hover {
      background-color: #e2e8f0;
    }

    /* Step Description Banner */
    .step-desc {
      background: #ffffff;
      border-left: 4px solid #0284c7;
      padding: 8px 12px;
      border-radius: 4px;
      font-size: 12.5px;
      line-height: 1.35;
      color: #334155;
      min-height: 44px;
      display: flex;
      align-items: center;
      box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    }
    .step-desc strong {
      color: #0284c7;
      margin-right: 4px;
    }

    /* SVG viewport */
    .diagram-box {
      width: 100%;
      position: relative;
      background: transparent;
      overflow: hidden;
    }

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

    /* SVG text styling */
    .label-subunit {
      font-size: 11px;
      font-weight: 800;
      fill: #475569;
      letter-spacing: 0.8px;
    }
    .label-rna {
      font-size: 12px;
      font-weight: 800;
      fill: #ffffff;
      font-family: monospace;
    }
    .base-text {
      font-size: 11px;
      font-weight: 700;
      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
      text-anchor: middle;
      dominant-baseline: central;
    }

    /* Native CSS Transitions */
    .anim-group {
      transition: transform 0.55s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.45s ease;
    }

    @media (max-width: 480px) {
      .step-btn {
        font-size: 11px;
        padding: 6px 2px;
      }
      .play-btn {
        font-size: 11px;
        min-width: 62px;
        padding: 6px 8px;
      }
      .step-desc {
        font-size: 11.5px;
        padding: 6px 8px;
        min-height: 40px;
      }
    }
  </style>
</head>
<body>

  <div class="main-wrap">
    
    <div class="controls">
      <div class="step-buttons">
        <button class="step-btn active" id="btn-0" onclick="setStep(0)">1. tRNA Entry</button>
        <button class="step-btn" id="btn-1" onclick="setStep(1)">2. Peptide Bond</button>
        <button class="step-btn" id="btn-2" onclick="setStep(2)">3. Translocation</button>
      </div>
      <button class="play-btn" id="play-toggle" onclick="togglePlay()">⏸ Pause</button>
    </div>

    
    <div class="step-desc" id="step-desc-text">
      <span><strong>Step 1:</strong> Aminoacyl-tRNA enters the <strong>A site</strong>, matching anticodon (AAG) with codon (UUC).</span>
    </div>

    
    <div class="diagram-box">
      <svg viewBox="0 0 600 375" id="ribo-svg">
        <defs>
          <linearGradient id="largeSubunitGrad" x1="0" y1="0" x2="0" y2="1">
            <stop offset="0%" stop-color="#e0e7ff" />
            <stop offset="100%" stop-color="#c7d2fe" />
          </linearGradient>
          <linearGradient id="smallSubunitGrad" x1="0" y1="0" x2="0" y2="1">
            <stop offset="0%" stop-color="#ede9fe" />
            <stop offset="100%" stop-color="#ddd6fe" />
          </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 1.5 L 9 5 L 0 8.5 z" fill="#ea580c" />
          </marker>
          <marker id="exitArrow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
            <path d="M 0 1.5 L 9 5 L 0 8.5 z" fill="#64748b" />
          </marker>
        </defs>

        
        <path d="M 65 235 
                 C 65 55, 160 18, 300 18 
                 C 440 18, 535 55, 535 235 
                 C 490 244, 420 248, 300 248 
                 C 180 248, 110 244, 65 235 Z" 
              fill="url(#largeSubunitGrad)" stroke="#a5b4fc" stroke-width="2" />
        
        
        <g transform="translate(470, 36)">
          <rect x="-65" y="-12" width="130" height="22" rx="11" fill="#c7d2fe" fill-opacity="0.8" stroke="#818cf8" stroke-width="1.2"/>
          <text x="0" y="3.5" text-anchor="middle" font-size="10" font-weight="800" fill="#3730a3" letter-spacing="0.5">LARGE SUBUNIT</text>
        </g>

        
        <path d="M 300 142 C 275 110, 235 70, 175 32" fill="none" stroke="#cbd5e1" stroke-width="14" stroke-linecap="round" opacity="0.6" />
        <path d="M 300 142 C 275 110, 235 70, 175 32" fill="none" stroke="#94a3b8" stroke-dasharray="3 3" stroke-width="1.5" />
        <text x="175" y="24" text-anchor="middle" font-size="9" font-weight="700" fill="#64748b" letter-spacing="0.3">Exit Tunnel</text>

        
        
        <g transform="translate(145, 78)">
          <rect x="0" y="0" width="86" height="162" rx="8" fill="#f1f5f9" fill-opacity="0.7" stroke="#cbd5e1" stroke-dasharray="4 3" stroke-width="1.5" />
          <rect x="28" y="8" width="30" height="16" rx="4" fill="#e2e8f0" />
          <text x="43" y="20" text-anchor="middle" font-size="11" font-weight="800" fill="#475569">E</text>
          <text x="43" y="34" text-anchor="middle" font-size="8.5" font-weight="700" fill="#64748b" letter-spacing="0.5">EXIT</text>
        </g>

        
        <g transform="translate(257, 78)">
          <rect x="0" y="0" width="86" height="162" rx="8" fill="#f1f5f9" fill-opacity="0.7" stroke="#cbd5e1" stroke-dasharray="4 3" stroke-width="1.5" />
          <rect x="28" y="8" width="30" height="16" rx="4" fill="#bae6fd" />
          <text x="43" y="20" text-anchor="middle" font-size="11" font-weight="800" fill="#0369a1">P</text>
          <text x="43" y="34" text-anchor="middle" font-size="8.5" font-weight="700" fill="#0284c7" letter-spacing="0.5">PEPTIDYL</text>
        </g>

        
        <g transform="translate(369, 78)">
          <rect x="0" y="0" width="86" height="162" rx="8" fill="#f1f5f9" fill-opacity="0.7" stroke="#cbd5e1" stroke-dasharray="4 3" stroke-width="1.5" />
          <rect x="28" y="8" width="30" height="16" rx="4" fill="#bbf7d0" />
          <text x="43" y="20" text-anchor="middle" font-size="11" font-weight="800" fill="#15803d">A</text>
          <text x="43" y="34" text-anchor="middle" font-size="8.5" font-weight="700" fill="#16a34a" letter-spacing="0.5">AMINOACYL</text>
        </g>

        
        <g id="mrna-strand">
          <rect x="35" y="254" width="530" height="28" rx="6" fill="#0284c7" />
          <text x="48" y="271" class="label-rna">5'</text>
          <text x="546" y="271" class="label-rna">3'</text>

          
          <rect x="155" y="258" width="66" height="20" rx="3" fill="#0369a1" stroke="#38bdf8" stroke-width="1" />
          <text x="188" y="269" class="base-text" fill="#ffffff">GCU</text>

          
          <rect x="267" y="258" width="66" height="20" rx="3" fill="#0369a1" stroke="#38bdf8" stroke-width="1" />
          <text x="300" y="269" class="base-text" fill="#ffffff">AUG</text>

          
          <rect x="379" y="258" width="66" height="20" rx="3" fill="#0369a1" stroke="#38bdf8" stroke-width="1" />
          <text x="412" y="269" class="base-text" fill="#ffffff">UUC</text>
        </g>

        
        <path d="M 80 286 
                 C 150 282, 450 282, 520 286 
                 C 535 335, 475 366, 300 366 
                 C 125 366, 65 335, 80 286 Z" 
              fill="url(#smallSubunitGrad)" stroke="#c4b5fd" stroke-width="2" />
        <text x="300" y="338" text-anchor="middle" class="label-subunit">SMALL SUBUNIT (30S/40S)</text>

        

        
        <g id="tRNA-E" class="anim-group" style="opacity: 0; transform: translate(0px, 0px);">
          <path d="M 188 238 L 188 206 C 188 196, 175 196, 175 182 C 175 168, 188 168, 188 156" 
                fill="none" stroke="#64748b" stroke-width="6" stroke-linecap="round" />
          <rect x="173" y="235" width="30" height="15" rx="3" fill="#64748b" />
          <text x="188" y="243" class="base-text" fill="#ffffff" font-size="9.5">CGA</text>
        </g>
        <path id="exit-arrow-path" class="anim-group" d="M 175 156 Q 135 135, 95 105" fill="none" stroke="#64748b" stroke-width="2.5" stroke-dasharray="4 3" marker-end="url(#exitArrow)" style="opacity: 0;" />

        
        <g id="tRNA-P" class="anim-group" style="opacity: 1; transform: translate(0px, 0px);">
          <path d="M 300 238 L 300 206 C 300 196, 287 196, 287 182 C 287 168, 300 168, 300 156" 
                fill="none" stroke="#0284c7" stroke-width="6" stroke-linecap="round" />
          <rect x="285" y="235" width="30" height="15" rx="3" fill="#0284c7" />
          <text x="300" y="243" class="base-text" fill="#ffffff" font-size="9.5">UAC</text>
        </g>

        
        <g id="tRNA-A" class="anim-group" style="opacity: 1; transform: translate(0px, 0px);">
          <path d="M 412 238 L 412 206 C 412 196, 399 196, 399 182 C 399 168, 412 168, 412 156" 
                fill="none" stroke="#16a34a" stroke-width="6" stroke-linecap="round" />
          <rect x="397" y="235" width="30" height="15" rx="3" fill="#16a34a" />
          <text x="412" y="243" class="base-text" fill="#ffffff" font-size="9.5">AAG</text>
          
          
          <circle id="aa-new" cx="412" cy="142" r="9.5" fill="#16a34a" stroke="#ffffff" stroke-width="1.5" />
          <text id="aa-new-txt" x="412" y="143" class="base-text" fill="#ffffff" font-size="8">Phe</text>
        </g>

        
        <g id="poly-chain" class="anim-group" style="opacity: 1; transform: translate(0px, 0px);">
          
          <path d="M 300 142 L 278 120 L 254 98 L 228 76 L 202 54" fill="none" stroke="#94a3b8" stroke-width="2" stroke-dasharray="2 1" />
          
          
          
          <circle cx="300" cy="142" r="9.5" fill="#ea580c" stroke="#ffffff" stroke-width="1.5" />
          <text x="300" y="143" class="base-text" fill="#ffffff" font-size="7.5">Met</text>

          
          <circle cx="278" cy="120" r="9.5" fill="#d97706" stroke="#ffffff" stroke-width="1.5" />
          <text x="278" y="121" class="base-text" fill="#ffffff" font-size="7.5">Ala</text>

          
          <circle cx="254" cy="98" r="9.5" fill="#2563eb" stroke="#ffffff" stroke-width="1.5" />
          <text x="254" y="99" class="base-text" fill="#ffffff" font-size="7.5">Ser</text>

          
          <circle cx="228" cy="76" r="9.5" fill="#9333ea" stroke="#ffffff" stroke-width="1.5" />
          <text x="228" y="77" class="base-text" fill="#ffffff" font-size="7.5">Leu</text>

          
          <circle cx="202" cy="54" r="9.5" fill="#0891b2" stroke="#ffffff" stroke-width="1.5" />
          <text x="202" y="55" class="base-text" fill="#ffffff" font-size="7.5">Gly</text>
        </g>

        
        <g id="bond-arrow-grp" class="anim-group" style="opacity: 0;">
          <path d="M 312 150 C 335 168, 375 168, 400 150" fill="none" stroke="#ea580c" stroke-width="2.5" stroke-dasharray="3 2" marker-end="url(#arrow)" />
          <g transform="translate(356, 172)">
            <rect x="-42" y="-10" width="84" height="20" rx="10" fill="#fff7ed" stroke="#ea580c" stroke-width="1.2" />
            <text x="0" y="3.5" text-anchor="middle" font-size="9.5" font-weight="800" fill="#c2410c">Peptide Bond</text>
          </g>
        </g>

      </svg>
    </div>
  </div>

  <script>
    let currentStep = 0;
    let autoPlay = true;
    let playTimer = null;

    const tP = document.getElementById('tRNA-P');
    const tA = document.getElementById('tRNA-A');
    const tE = document.getElementById('tRNA-E');
    const poly = document.getElementById('poly-chain');
    const bArrow = document.getElementById('bond-arrow-grp');
    const eArrow = document.getElementById('exit-arrow-path');
    const playBtn = document.getElementById('play-toggle');
    const descText = document.getElementById('step-desc-text');

    const descriptions = [
      "<span><strong>Step 1:</strong> Aminoacyl-tRNA enters the <strong>A site</strong>, matching anticodon (AAG) with codon (UUC).</span>",
      "<span><strong>Step 2:</strong> <strong>Peptide bond forms</strong>; growing polypeptide chain is transferred from P-site to A-site tRNA.</span>",
      "<span><strong>Step 3:</strong> <strong>Translocation:</strong> Ribosome advances; uncharged tRNA moves to E site and exits; peptidyl-tRNA shifts to P site.</span>"
    ];

    function renderStep(idx) {
      currentStep = idx;
      
      // Update Tab UI
      for (let i = 0; i < 3; i++) {
        document.getElementById('btn-' + i).classList.toggle('active', i === idx);
      }
      descText.innerHTML = descriptions[idx];

      if (idx === 0) {
        // Step 1: Entry / Codon matching
        tA.style.opacity = '1';
        tA.style.transform = 'translate(0px, 0px)';

        tP.style.opacity = '1';
        tP.style.transform = 'translate(0px, 0px)';

        poly.style.opacity = '1';
        poly.style.transform = 'translate(0px, 0px)';

        tE.style.opacity = '0';
        tE.style.transform = 'translate(0px, 0px)';

        bArrow.style.opacity = '0';
        eArrow.style.opacity = '0';
      } 
      else if (idx === 1) {
        // Step 2: Peptide bond forming (chain shifts onto A-site tRNA)
        tA.style.opacity = '1';
        tA.style.transform = 'translate(0px, 0px)';

        tP.style.opacity = '1';
        tP.style.transform = 'translate(0px, 0px)';

        bArrow.style.opacity = '1';
        // Polypeptide chain shifts +112px X to attach to Phe on A-site tRNA
        poly.style.opacity = '1';
        poly.style.transform = 'translate(112px, 0px)';

        tE.style.opacity = '0';
        eArrow.style.opacity = '0';
      } 
      else if (idx === 2) {
        // Step 3: Translocation
        bArrow.style.opacity = '0';
        
        // tRNA at E site becomes visible & exit arrow triggers
        tE.style.opacity = '1';
        tE.style.transform = 'translate(0px, 0px)';
        eArrow.style.opacity = '1';
        
        // P-site uncharged tRNA moves left towards E and fades
        tP.style.opacity = '0.35';
        tP.style.transform = 'translate(-112px, 0px)';
        
        // A-site tRNA (now holding polypeptide) shifts into P site (-112px)
        tA.style.opacity = '1';
        tA.style.transform = 'translate(-112px, 0px)';
        
        // Polypeptide stays attached to the shifted tRNA (net 0 relative to P site)
        poly.style.opacity = '1';
        poly.style.transform = 'translate(0px, 0px)';
      }
    }

    function setStep(idx) {
      renderStep(idx);
    }

    function nextStep() {
      let next = (currentStep + 1) % 3;
      renderStep(next);
    }

    function startTimer() {
      if (playTimer) clearInterval(playTimer);
      playTimer = setInterval(() => {
        if (autoPlay) nextStep();
      }, 3400);
    }

    function togglePlay() {
      autoPlay = !autoPlay;
      playBtn.textContent = autoPlay ? "⏸ Pause" : "▶ Play";
      if (autoPlay) {
        nextStep();
        startTimer();
      } else {
        if (playTimer) clearInterval(playTimer);
      }
    }

    // Initial load
    renderStep(0);
    startTimer();
  </script>
</body>
</html>

The Central Dogma: DNA to RNA to Protein

<!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;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      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;
      min-height: 100%;
      padding: 10px 8px;
    }

    .decoder {
      width: 100%;
      max-width: 560px;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    /* Controls */
    .controls {
      display: flex;
      justify-content: center;
      gap: 6px;
      margin-bottom: 4px;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 4px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .btn:hover, .btn.active {
      background: #2563eb;
      border-color: #2563eb;
      color: #ffffff;
    }

    /* Section Row */
    .row-container {
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .row-label {
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.5px;
      text-transform: uppercase;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 4px;
    }

    .dna-label { color: #1d4ed8; }
    .mrna-label { color: #15803d; }
    .trna-label { color: #b45309; }
    .poly-label { color: #7e22ce; }

    .grid-row {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
    }

    /* Triplet / Codon / Amino Box */
    .triplet {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 3px;
      padding: 6px 4px;
      border-radius: 8px;
      cursor: pointer;
      transition: opacity 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
      position: relative;
    }

    .base {
      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
      font-size: 16px;
      font-weight: 700;
      letter-spacing: 1px;
    }

    /* Specific Row Styles */
    .dna-box {
      background: #eff6ff;
      border: 1px solid #bfdbfe;
      color: #1e40af;
    }

    .mrna-box {
      background: #f0fdf4;
      border: 1px solid #bbf7d0;
      color: #166534;
    }

    .trna-box {
      background: #fffbeb;
      border: 1px solid #fde68a;
      color: #92400e;
    }

    /* Polypeptide */
    .peptide-row {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      position: relative;
    }

    .amino-badge {
      background: #faf5ff;
      border: 1px solid #e9d5ff;
      color: #6b21a8;
      border-radius: 20px;
      padding: 6px 2px;
      text-align: center;
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      line-height: 1.1;
      transition: opacity 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    }

    .amino-sub {
      font-size: 10px;
      font-weight: 600;
      opacity: 0.8;
      margin-top: 1px;
    }

    /* Peptide Bond Connector Line */
    .peptide-row::before {
      content: "";
      position: absolute;
      top: 50%;
      left: 15%;
      right: 15%;
      height: 2px;
      background: #d8b4fe;
      z-index: 0;
      transform: translateY(-50%);
    }

    .amino-badge {
      position: relative;
      z-index: 1;
    }

    /* Process Arrows */
    .process-arrow {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      font-size: 11px;
      font-weight: 600;
      color: #64748b;
      padding: 1px 0;
    }

    .process-arrow span {
      display: inline-block;
      font-size: 12px;
      line-height: 1;
    }

    /* Selection / Active Highlighting */
    .dimmed {
      opacity: 0.25;
    }

    .highlighted.dna-box {
      background: #dbeafe;
      box-shadow: 0 0 0 2px #3b82f6;
    }

    .highlighted.mrna-box {
      background: #dcfce7;
      box-shadow: 0 0 0 2px #22c55e;
    }

    .highlighted.trna-box {
      background: #fef3c7;
      box-shadow: 0 0 0 2px #f59e0b;
    }

    .highlighted.amino-badge {
      background: #f3e8ff;
      box-shadow: 0 0 0 2px #a855f7;
    }

    .direction {
      font-size: 10px;
      font-weight: 500;
      opacity: 0.7;
    }
  </style>
</head>
<body>

  <div class="decoder">
    
    <div class="controls">
      <button class="btn active" onclick="setColumn('all')">All Codons</button>
      <button class="btn" onclick="setColumn(0)">1: Met</button>
      <button class="btn" onclick="setColumn(1)">2: Pro</button>
      <button class="btn" onclick="setColumn(2)">3: Asn</button>
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    <div class="row-container">
      <div class="row-label dna-label">
        <span>DNA Template</span>
        <span class="direction">3' → 5'</span>
      </div>
      <div class="grid-row">
        <div class="triplet dna-box col-0" onclick="setColumn(0)">
          <span class="base">TAC</span>
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          <span class="base">GGC</span>
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        <div class="triplet dna-box col-2" onclick="setColumn(2)">
          <span class="base">TTA</span>
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      </div>
    </div>

    
    <div class="process-arrow">
      <span>↓</span> Transcription <span>↓</span>
    </div>

    
    <div class="row-container">
      <div class="row-label mrna-label">
        <span>mRNA Codons</span>
        <span class="direction">5' → 3'</span>
      </div>
      <div class="grid-row">
        <div class="triplet mrna-box col-0" onclick="setColumn(0)">
          <span class="base">AUG</span>
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          <span class="base">CCG</span>
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        <div class="triplet mrna-box col-2" onclick="setColumn(2)">
          <span class="base">AAU</span>
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      </div>
    </div>

    
    <div class="process-arrow">
      <span>↓</span> Translation <span>↓</span>
    </div>

    
    <div class="row-container">
      <div class="row-label trna-label">
        <span>tRNA Anticodons</span>
        <span class="direction">3' → 5'</span>
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          <span class="base">UAC</span>
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        <div class="triplet trna-box col-2" onclick="setColumn(2)">
          <span class="base">UUA</span>
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      </div>
    </div>

    
    <div class="process-arrow">
      <span>↓</span> Peptide Synthesis <span>↓</span>
    </div>

    
    <div class="row-container">
      <div class="row-label poly-label">
        <span>Polypeptide Chain</span>
        <span class="direction">N → C</span>
      </div>
      <div class="peptide-row">
        <div class="amino-badge col-0" onclick="setColumn(0)">
          <span>Methionine</span>
          <span class="amino-sub">(Start)</span>
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        <div class="amino-badge col-1" onclick="setColumn(1)">
          <span>Proline</span>
        </div>
        <div class="amino-badge col-2" onclick="setColumn(2)">
          <span>Asparagine</span>
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      </div>
    </div>
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</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; }
    html, body {
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      position: absolute;
      left: 5px;
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        padding: 4px 9px;
        font-size: 11px;
      }
      .legend {
        font-size: 10px;
        gap: 8px;
      }
    }
  </style>
</head>
<body>

  <div class="container">
    
    <div class="toolbar" role="tablist">
      <button class="btn-tab active" data-mode="all">All Flows</button>
      <button class="btn-tab" data-mode="standard">Standard</button>
      <button class="btn-tab" data-mode="special">Exceptions</button>
      <button class="btn-tab" data-mode="blocked">Impossible</button>
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    <div class="diagram-area">
      <svg viewBox="0 0 620 345" preserveAspectRatio="xMidYMid meet">
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          <path d="M 80 120 C 45 52, 145 52, 110 117" fill="none" stroke="#16a34a" stroke-width="3" marker-end="url(#arrow-green)" />
          <text x="95" y="44" text-anchor="middle" font-size="12" font-weight="700" fill="#16a34a">Replication</text>
        </g>

        
        <g class="pathway path-standard" id="flow-transcription">
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          <text x="202" y="142" text-anchor="middle" font-size="12" font-weight="700" fill="#16a34a">Transcription</text>
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          <text x="417" y="142" text-anchor="middle" font-size="12" font-weight="700" fill="#16a34a">Translation</text>
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        <g class="pathway path-special" id="flow-rna-rep">
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          <text x="310" y="36" text-anchor="middle" font-size="12" font-weight="700" fill="#ea580c">RNA Replication</text>
          <text x="310" y="50" text-anchor="middle" font-size="10" font-weight="600" fill="#9a3412">(RNA Viruses)</text>
        </g>

        
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        </g>

        
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          <text x="300" y="318" text-anchor="middle" font-size="9.5" font-weight="600" fill="#b91c1c">Sequence info cannot flow from protein to nucleic acid</text>
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        </g>

        
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          <text x="55" y="48" text-anchor="middle" font-size="11" font-weight="600" fill="#a855f7">Functional Cell</text>
        </g>
      </svg>
    </div>

    
    <div class="legend">
      <div class="legend-item">
        <span class="legend-line line-std"></span> Standard
      </div>
      <div class="legend-item">
        <span class="legend-line line-special"></span> Special Exception
      </div>
      <div class="legend-item">
        <span class="legend-line line-blocked"></span> Impossible Transfer
      </div>
    </div>
  </div>

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</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, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      padding: 12px 8px;
      user-select: none;
      -webkit-user-select: none;
    }

    .schema-container {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 14px;
    }

    /* Top Flow Row */
    .flow-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      position: relative;
      margin-top: 42px; /* clearance for replication loop */
    }

    /* Node Cards */
    .node-wrap {
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      flex: 0 0 80px;
      cursor: pointer;
    }

    .node-card {
      width: 80px;
      height: 90px;
      border-radius: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 5px;
      transition: box-shadow 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
      background: #f8fafc;
      border: 2px solid #e2e8f0;
      position: relative;
      z-index: 2;
    }

    .node-dna {
      border-color: #93c5fd;
      background: #eff6ff;
    }
    .node-dna.active {
      border-color: #2563eb;
      box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.25);
    }

    .node-rna {
      border-color: #86efac;
      background: #f0fdf4;
    }
    .node-rna.active {
      border-color: #16a34a;
      box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.25);
    }

    .node-protein {
      border-color: #d8b4fe;
      background: #faf5ff;
    }
    .node-protein.active {
      border-color: #9333ea;
      box-shadow: 0 0 0 3px rgba(147, 51, 234, 0.25);
    }

    .node-title {
      font-size: 13px;
      font-weight: 700;
      letter-spacing: 0.5px;
    }
    .node-dna .node-title { color: #1d4ed8; }
    .node-rna .node-title { color: #15803d; }
    .node-protein .node-title { color: #7e22ce; }

    .node-icon {
      width: 36px;
      height: 36px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* Replication Loop - anchored firmly on DNA node */
    .replication-loop {
      position: absolute;
      bottom: 100%;
      left: 50%;
      transform: translateX(-50%);
      margin-bottom: 2px;
      display: flex;
      flex-direction: column;
      align-items: center;
      pointer-events: none;
      width: 74px;
    }

    .loop-label {
      font-size: 9.5px;
      font-weight: 700;
      color: #2563eb;
      background: #ffffff;
      padding: 0 3px;
      line-height: 1;
      white-space: nowrap;
      margin-bottom: -4px;
      z-index: 3;
    }

    .loop-sub {
      font-size: 8px;
      font-weight: 600;
      color: #3b82f6;
      white-space: nowrap;
      margin-top: -1px;
    }

    .loop-svg {
      width: 58px;
      height: 22px;
      overflow: visible;
    }

    /* Process Arrows */
    .process-arrow {
      flex: 1 1 0;
      min-width: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 0 4px;
    }

    .arrow-text-main {
      font-size: 11.5px;
      font-weight: 700;
      color: #334155;
      text-align: center;
      line-height: 1.15;
      white-space: normal;
    }

    .arrow-text-sub {
      font-size: 9.5px;
      font-weight: 600;
      color: #64748b;
      margin-top: 1px;
      text-align: center;
      line-height: 1.1;
      white-space: normal;
    }

    .arrow-svg {
      width: 100%;
      height: 14px;
      margin: 2px 0;
      max-width: 110px;
    }

    /* Detail View Container */
    .detail-container {
      width: 100%;
      height: 106px;
      position: relative;
      margin-top: 2px;
    }

    .detail-card {
      position: absolute;
      inset: 0;
      border-radius: 12px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 8px;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.2s ease, transform 0.2s ease;
      transform: translateY(4px);
      border: 1px solid #e2e8f0;
      background: #f8fafc;
    }

    .detail-card.active {
      opacity: 1;
      pointer-events: auto;
      transform: translateY(0);
    }

    .detail-dna {
      background: #eff6ff;
      border-color: #bfdbfe;
    }
    .detail-rna {
      background: #f0fdf4;
      border-color: #bbf7d0;
    }
    .detail-protein {
      background: #faf5ff;
      border-color: #e9d5ff;
    }

    .detail-left {
      display: flex;
      flex-direction: column;
      gap: 3px;
      min-width: 0;
    }

    .detail-tag {
      font-size: 10px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }
    .detail-dna .detail-tag { color: #1d4ed8; }
    .detail-rna .detail-tag { color: #15803d; }
    .detail-protein .detail-tag { color: #7e22ce; }

    .detail-location {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
      display: flex;
      align-items: center;
      gap: 4px;
      line-height: 1.2;
    }

    .detail-sub {
      font-size: 11.5px;
      color: #475569;
      font-weight: 500;
      line-height: 1.2;
    }

    .detail-pill {
      font-size: 11px;
      font-weight: 600;
      padding: 5px 10px;
      border-radius: 16px;
      background: #ffffff;
      box-shadow: 0 1px 2px rgba(0,0,0,0.06);
      flex-shrink: 0;
      text-align: center;
    }
    .detail-dna .detail-pill { color: #1e40af; border: 1px solid #bfdbfe; }
    .detail-rna .detail-pill { color: #166534; border: 1px solid #bbf7d0; }
    .detail-protein .detail-pill { color: #6b21a8; border: 1px solid #e9d5ff; }

    /* Interactive Stepper Navigation */
    .stepper-nav {
      display: flex;
      gap: 6px;
      justify-content: center;
      width: 100%;
    }

    .step-btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 16px;
      font-size: 11.5px;
      font-weight: 600;
      color: #475569;
      padding: 4px 10px;
      cursor: pointer;
      transition: background 0.15s, color 0.15s, border-color 0.15s;
    }

    .step-btn.active {
      background: #1e2945;
      color: #ffffff;
      border-color: #1e2945;
    }

    /* Responsive styling for screens under 440px */
    @media (max-width: 440px) {
      .node-wrap {
        flex: 0 0 64px;
      }
      .node-card {
        width: 64px;
        height: 76px;
        border-radius: 10px;
        gap: 3px;
      }
      .node-icon {
        width: 28px;
        height: 28px;
      }
      .node-title {
        font-size: 11px;
      }
      .process-arrow {
        padding: 0 2px;
      }
      .arrow-text-main {
        font-size: 10px;
      }
      .arrow-text-sub {
        font-size: 8px;
      }
      .replication-loop {
        width: 62px;
      }
      .loop-label {
        font-size: 8.5px;
      }
      .loop-sub {
        font-size: 7.5px;
      }
      .loop-svg {
        width: 46px;
        height: 18px;
      }
      .detail-location {
        font-size: 13px;
      }
      .detail-sub {
        font-size: 10.5px;
      }
      .detail-pill {
        font-size: 10px;
        padding: 4px 7px;
      }
      .step-btn {
        font-size: 11px;
        padding: 3px 8px;
      }
    }

    /* Extra compact layout for screens under 360px */
    @media (max-width: 360px) {
      .node-wrap {
        flex: 0 0 54px;
      }
      .node-card {
        width: 54px;
        height: 70px;
        border-radius: 8px;
      }
      .node-icon {
        width: 24px;
        height: 24px;
      }
      .node-title {
        font-size: 10px;
      }
      .arrow-text-main {
        font-size: 9px;
      }
      .arrow-text-sub {
        font-size: 7.5px;
      }
      .detail-card {
        padding: 8px 10px;
        flex-direction: column;
        align-items: flex-start;
        justify-content: center;
        gap: 5px;
      }
      .detail-pill {
        align-self: flex-start;
      }
      .detail-container {
        height: 114px;
      }
    }
  </style>
</head>
<body>

<div class="schema-container">
  
  
  <div class="flow-row">
    
    
    <div class="node-wrap" onclick="selectNode(0)" id="wrap-0">
      
      <div class="replication-loop">
        <span class="loop-label">Replication</span>
        <svg class="loop-svg" viewBox="0 0 54 22">
          <defs>
            <marker id="arrow-blue" markerWidth="5" markerHeight="5" refX="4" refY="2.5" orient="auto">
              <polygon points="0 0, 5 2.5, 0 5" fill="#2563eb" />
            </marker>
          </defs>
          <path d="M 10,20 C 2,2 52,2 44,18" fill="none" stroke="#2563eb" stroke-width="2" stroke-dasharray="3,1.5" marker-end="url(#arrow-blue)" />
        </svg>
        <span class="loop-sub">DNA Polymerase</span>
      </div>

      <div class="node-card node-dna active" id="card-0">
        
        <svg class="node-icon" viewBox="0 0 32 32">
          <path d="M 8,6 Q 16,14 24,6" fill="none" stroke="#2563eb" stroke-width="2.5" stroke-linecap="round"/>
          <path d="M 24,6 Q 16,14 8,22" fill="none" stroke="#3b82f6" stroke-width="2.5" stroke-linecap="round"/>
          <path d="M 8,22 Q 16,30 24,22" fill="none" stroke="#2563eb" stroke-width="2.5" stroke-linecap="round"/>
          <line x1="11" y1="9" x2="21" y2="9" stroke="#93c5fd" stroke-width="1.8"/>
          <circle cx="16" cy="14" r="1.2" fill="#93c5fd"/>
          <line x1="11" y1="19" x2="21" y2="19" stroke="#93c5fd" stroke-width="1.8"/>
          <line x1="11" y1="25" x2="21" y2="25" stroke="#93c5fd" stroke-width="1.8"/>
        </svg>
        <span class="node-title">DNA</span>
      </div>
    </div>

    
    <div class="process-arrow">
      <span class="arrow-text-main">Transcription</span>
      <svg class="arrow-svg" viewBox="0 0 80 12" preserveAspectRatio="none">
        <defs>
          <marker id="arrow-gray" markerWidth="5" markerHeight="5" refX="4" refY="2.5" orient="auto">
            <polygon points="0 0, 5 2.5, 0 5" fill="#64748b"/>
          </marker>
        </defs>
        <line x1="2" y1="6" x2="74" y2="6" stroke="#64748b" stroke-width="2.2" marker-end="url(#arrow-gray)"/>
      </svg>
      <span class="arrow-text-sub">RNA Polymerase</span>
    </div>

    
    <div class="node-wrap" onclick="selectNode(1)" id="wrap-1">
      <div class="node-card node-rna" id="card-1">
        
        <svg class="node-icon" viewBox="0 0 32 32">
          <path d="M 10,4 Q 22,12 10,20 Q 22,28 10,32" fill="none" stroke="#16a34a" stroke-width="2.6" stroke-linecap="round"/>
          <line x1="15" y1="8" x2="23" y2="8" stroke="#86efac" stroke-width="2" stroke-linecap="round"/>
          <line x1="12" y1="16" x2="20" y2="16" stroke="#86efac" stroke-width="2" stroke-linecap="round"/>
          <line x1="15" y1="24" x2="23" y2="24" stroke="#86efac" stroke-width="2" stroke-linecap="round"/>
        </svg>
        <span class="node-title">RNA</span>
      </div>
    </div>

    
    <div class="process-arrow">
      <span class="arrow-text-main">Translation</span>
      <svg class="arrow-svg" viewBox="0 0 80 12" preserveAspectRatio="none">
        <line x1="2" y1="6" x2="74" y2="6" stroke="#64748b" stroke-width="2.2" marker-end="url(#arrow-gray)"/>
      </svg>
      <span class="arrow-text-sub">Ribosome</span>
    </div>

    
    <div class="node-wrap" onclick="selectNode(2)" id="wrap-2">
      <div class="node-card node-protein" id="card-2">
        
        <svg class="node-icon" viewBox="0 0 32 32">
          <circle cx="8" cy="10" r="3.2" fill="#c084fc"/>
          <circle cx="16" cy="8" r="3.2" fill="#9333ea"/>
          <circle cx="23" cy="12" r="3.2" fill="#a855f7"/>
          <circle cx="21" cy="20" r="3.2" fill="#7e22ce"/>
          <circle cx="13" cy="22" r="3.2" fill="#a855f7"/>
          <circle cx="9" cy="16" r="3.2" fill="#9333ea"/>
          <path d="M 8,10 L 16,8 L 23,12 L 21,20 L 13,22 L 9,16" fill="none" stroke="#7e22ce" stroke-width="1.4" stroke-dasharray="1.5,1.5"/>
        </svg>
        <span class="node-title">Protein</span>
      </div>
    </div>

  </div>

  
  <div class="detail-container">
    
    
    <div class="detail-card detail-dna active" id="detail-0">
      <div class="detail-left">
        <span class="detail-tag">Storage Stage</span>
        <div class="detail-location">📍 Nucleus</div>
        <div class="detail-sub">DNA Polymerase duplicates genetic code</div>
      </div>
      <div class="detail-pill">Double Helix Blueprint</div>
    </div>

    
    <div class="detail-card detail-rna" id="detail-1">
      <div class="detail-left">
        <span class="detail-tag">Messenger Stage</span>
        <div class="detail-location">📍 Nucleus → Cytoplasm</div>
        <div class="detail-sub">RNA Polymerase transcribes into mRNA</div>
      </div>
      <div class="detail-pill">Single Strand Mobile Code</div>
    </div>

    
    <div class="detail-card detail-protein" id="detail-2">
      <div class="detail-left">
        <span class="detail-tag">Functional Machinery</span>
        <div class="detail-location">📍 Ribosome (Cytoplasm)</div>
        <div class="detail-sub">Ribosome translates code into amino acids</div>
      </div>
      <div class="detail-pill">Folded 3D Structure</div>
    </div>

  </div>

  
  <div class="stepper-nav">
    <button class="step-btn active" id="btn-0" onclick="selectNode(0)">1. DNA</button>
    <button class="step-btn" id="btn-1" onclick="selectNode(1)">2. RNA</button>
    <button class="step-btn" id="btn-2" onclick="selectNode(2)">3. Protein</button>
  </div>

</div>

<script>
  function selectNode(index) {
    for (let i = 0; i < 3; i++) {
      const isCurrent = i === index;
      document.getElementById(`card-${i}`).classList.toggle('active', isCurrent);
      document.getElementById(`detail-${i}`).classList.toggle('active', isCurrent);
      document.getElementById(`btn-${i}`).classList.toggle('active', isCurrent);
    }
  }
</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>Transcription Bubble</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      width: 100%;
      min-height: 100%;
      background: #ffffff;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 10px 12px;
      user-select: none;
      -webkit-user-select: none;
    }

    .header-bar {
      width: 100%;
      max-width: 620px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 6px;
    }

    .badge {
      display: inline-flex;
      align-items: center;
      gap: 4px;
      padding: 3px 8px;
      border-radius: 999px;
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.2px;
    }

    .badge-coding { background: #eff6ff; color: #2563eb; border: 1px solid #bfdbfe; }
    .badge-template { background: #f5f3ff; color: #7c3aed; border: 1px solid #ddd6fe; }
    .badge-rna { background: #ecfdf5; color: #059669; border: 1px solid #a7f3d0; }

    .diagram-stage {
      width: 100%;
      max-width: 620px;
      aspect-ratio: 16 / 9;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    .pairing-bar {
      width: 100%;
      max-width: 620px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 6px 10px;
      display: flex;
      justify-content: space-around;
      align-items: center;
      flex-wrap: wrap;
      gap: 6px;
    }

    .pair-item {
      display: flex;
      align-items: center;
      gap: 4px;
      font-size: 12px;
      font-weight: 700;
    }

    .base-chip {
      display: inline-block;
      width: 18px;
      height: 18px;
      line-height: 18px;
      text-align: center;
      border-radius: 4px;
      font-size: 11px;
      font-weight: 800;
      color: #fff;
    }

    .b-a { background: #3b82f6; }
    .b-t { background: #ef4444; }
    .b-u { background: #10b981; }
    .b-c { background: #f59e0b; }
    .b-g { background: #8b5cf6; }

    .ctrl-bar {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-top: 4px;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #334155;
      padding: 4px 10px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, color 0.2s;
    }

    .btn:hover {
      background: #e2e8f0;
      color: #0f172a;
    }

    .btn.active {
      background: #2563eb;
      border-color: #2563eb;
      color: #ffffff;
    }

    /* Animation effects */
    @keyframes pulse-polymerase {
      0%, 100% { transform: scale(1); }
      50% { transform: scale(1.015); }
    }

    .poly-shape {
      transform-origin: 320px 145px;
      animation: pulse-polymerase 4s ease-in-out infinite;
    }

    .dash-flow {
      stroke-dasharray: 4 4;
      animation: flow 1.5s linear infinite;
    }

    @keyframes flow {
      to { stroke-dashoffset: -16; }
    }
  </style>
</head>
<body>

  
  <div class="header-bar">
    <span class="badge badge-coding">Coding 5' → 3'</span>
    <span class="badge badge-rna">mRNA 5' → 3'</span>
    <span class="badge badge-template">Template 3' → 5'</span>
  </div>

  
  <div class="diagram-stage">
    <svg viewBox="0 0 640 290">
      <defs>
        
        <marker id="arr-blue" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
          <path d="M0,0 L6,3 L0,6 Z" fill="#3b82f6" />
        </marker>
        <marker id="arr-purple" markerWidth="6" markerHeight="6" refX="1" refY="3" orient="auto">
          <path d="M6,0 L0,3 L6,6 Z" fill="#7c3aed" />
        </marker>
        <marker id="arr-green" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
          <path d="M0,0 L6,3 L0,6 Z" fill="#10b981" />
        </marker>
        <linearGradient id="polyGrad" x1="0%" y1="0%" x2="100%" y2="100%">
          <stop offset="0%" stop-color="#fdba74" stop-opacity="0.5" />
          <stop offset="100%" stop-color="#ea580c" stop-opacity="0.35" />
        </linearGradient>
      </defs>

      
      <g id="polyGroup" class="poly-shape">
        <ellipse cx="325" cy="142" rx="145" ry="92" fill="url(#polyGrad)" stroke="#ea580c" stroke-width="2.5" stroke-dasharray="8 4" />
        
        <g transform="translate(420, 70)">
          <path d="M0 0 L24 0 M18 -4 L24 0 L18 4" stroke="#ea580c" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round" fill="none" />
        </g>
        <text x="325" y="70" text-anchor="middle" fill="#c2410c" font-size="13" font-weight="800" letter-spacing="0.5">RNA Polymerase</text>
      </g>

      
      <g stroke="#cbd5e1" stroke-width="2">
        <line x1="35" y1="122" x2="35" y2="162" />
        <line x1="60" y1="122" x2="60" y2="162" />
        <line x1="85" y1="122" x2="85" y2="162" />
        <line x1="110" y1="122" x2="110" y2="162" />
        <line x1="135" y1="122" x2="135" y2="162" />
      </g>

      
      <g stroke="#cbd5e1" stroke-width="2">
        <line x1="515" y1="122" x2="515" y2="162" />
        <line x1="540" y1="122" x2="540" y2="162" />
        <line x1="565" y1="122" x2="565" y2="162" />
        <line x1="590" y1="122" x2="590" y2="162" />
        <line x1="615" y1="122" x2="615" y2="162" />
      </g>

      
      <path d="M 20 122 L 150 122 C 210 122, 230 92, 325 92 C 420 92, 440 122, 500 122 L 625 122"
            fill="none" stroke="#3b82f6" stroke-width="3.5" stroke-linecap="round" marker-end="url(#arr-blue)" />

      
      <path d="M 20 162 L 150 162 C 210 162, 230 192, 325 192 C 420 192, 440 162, 500 162 L 625 162"
            fill="none" stroke="#7c3aed" stroke-width="3.5" stroke-linecap="round" marker-start="url(#arr-purple)" />

      
      <g font-size="11" font-weight="700" text-anchor="middle" fill="#2563eb">
        <text x="240" y="85">A</text>
        <text x="275" y="81">T</text>
        <text x="310" y="80">G</text>
        <text x="345" y="80">C</text>
        <text x="380" y="81">A</text>
        <text x="415" y="85">T</text>
      </g>

      
      
      <line x1="260" y1="190" x2="260" y2="152" stroke="#64748b" stroke-width="1.5" stroke-dasharray="2 2" />
      <circle cx="260" cy="192" r="8" fill="#ef4444" />
      <text x="260" y="196" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">T</text>
      <circle cx="260" cy="150" r="8" fill="#3b82f6" />
      <text x="260" y="154" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">A</text>

      
      <line x1="298" y1="192" x2="298" y2="154" stroke="#64748b" stroke-width="1.5" stroke-dasharray="2 2" />
      <circle cx="298" cy="192" r="8" fill="#3b82f6" />
      <text x="298" y="196" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">A</text>
      <circle cx="298" cy="152" r="8" fill="#10b981" />
      <text x="298" y="156" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">U</text>

      
      <line x1="336" y1="192" x2="336" y2="158" stroke="#64748b" stroke-width="1.5" stroke-dasharray="2 2" />
      <circle cx="336" cy="192" r="8" fill="#f59e0b" />
      <text x="336" y="196" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">C</text>
      <circle cx="336" cy="156" r="8" fill="#8b5cf6" />
      <text x="336" y="160" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">G</text>

      
      <line x1="374" y1="192" x2="374" y2="164" stroke="#64748b" stroke-width="1.5" stroke-dasharray="2 2" />
      <circle cx="374" cy="192" r="8" fill="#8b5cf6" />
      <text x="374" y="196" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">G</text>
      <circle cx="374" cy="162" r="8" fill="#f59e0b" />
      <text x="374" y="166" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">C</text>

      
      <circle cx="412" cy="186" r="8" fill="#3b82f6" />
      <text x="412" y="190" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">A</text>
      <circle cx="450" cy="174" r="8" fill="#ef4444" />
      <text x="450" y="178" text-anchor="middle" fill="#fff" font-size="10" font-weight="800">T</text>

      
      <path id="mrnaPath" d="M 120 220 C 170 220, 200 148, 260 150 L 385 163"
            fill="none" stroke="#10b981" stroke-width="4" stroke-linecap="round" />

      
      <g transform="translate(112, 220)">
        <circle cx="0" cy="0" r="11" fill="#10b981" />
        <text x="0" y="4" text-anchor="middle" fill="#fff" font-size="11" font-weight="800">5'</text>
      </g>
      
      <g transform="translate(396, 165)">
        <circle cx="0" cy="0" r="9" fill="#059669" />
        <text x="0" y="3.5" text-anchor="middle" fill="#fff" font-size="9" font-weight="800">3'</text>
      </g>

      
      <text x="14" y="116" font-size="11" font-weight="800" fill="#2563eb">5'</text>
      <text x="14" y="176" font-size="11" font-weight="800" fill="#7c3aed">3'</text>
      <text x="618" y="116" font-size="11" font-weight="800" fill="#2563eb">3'</text>
      <text x="618" y="176" font-size="11" font-weight="800" fill="#7c3aed">5'</text>
    </svg>
  </div>

  
  <div class="pairing-bar">
    <div class="pair-item">
      <span class="base-chip b-a">A</span>
      <span>→</span>
      <span class="base-chip b-u">U</span>
    </div>
    <div class="pair-item">
      <span class="base-chip b-t">T</span>
      <span>→</span>
      <span class="base-chip b-a">A</span>
    </div>
    <div class="pair-item">
      <span class="base-chip b-c">C</span>
      <span>→</span>
      <span class="base-chip b-g">G</span>
    </div>
    <div class="pair-item">
      <span class="base-chip b-g">G</span>
      <span>→</span>
      <span class="base-chip b-c">C</span>
    </div>
  </div>

  
  <div class="ctrl-bar">
    <button class="btn active" id="btnToggle">⏸ Pause</button>
    <button class="btn" id="btnStep">Step ➔</button>
  </div>

  <script>
    const polyGroup = document.getElementById('polyGroup');
    const mrnaPath = document.getElementById('mrnaPath');
    const btnToggle = document.getElementById('btnToggle');
    const btnStep = document.getElementById('btnStep');

    let playing = true;
    let shiftOffset = 0;

    function applyShift(offset) {
      polyGroup.style.transform = `translateX(${offset}px)`;
    }

    btnToggle.addEventListener('click', () => {
      playing = !playing;
      btnToggle.textContent = playing ? '⏸ Pause' : '▶ Play';
      btnToggle.classList.toggle('active', playing);
    });

    btnStep.addEventListener('click', () => {
      shiftOffset = (shiftOffset + 8) % 32;
      applyShift(shiftOffset);
    });

    // Subtle gentle drift cycle
    let tick = 0;
    setInterval(() => {
      if (!playing) return;
      tick += 0.04;
      const offset = Math.sin(tick) * 10;
      applyShift(offset);
    }, 50);
  </script>
</body>
</html>

OGS.11.LS.EV.1

Aligned learning resources

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