<!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;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    }

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

    .header-section {
      text-align: center;
      margin-bottom: 12px;
    }

    .title {
      font-size: 17px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 6px;
      line-height: 1.2;
    }

    .badge-tag {
      display: inline-block;
      font-size: 11px;
      font-weight: 600;
      color: #ffffff;
      background: #1e2945;
      border: 1px solid #e2e8f0;
      padding: 3px 10px;
      border-radius: 12px;
      letter-spacing: 0.3px;
    }

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

    @media (max-width: 480px) {
      .cards-grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }

    .char-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 14px;
      padding: 14px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      position: relative;
      cursor: pointer;
      user-select: none;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    }

    .char-card:focus-visible {
      outline: 2px solid #22b7ff;
    }

    .char-card.active {
      border-color: #22b7ff;
      background: #f8fbff;
      box-shadow: 0 0 0 1px #22b7ff;
    }

    .card-label {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 8px;
    }

    .icon-container {
      width: 64px;
      height: 64px;
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      background: #f1f5f9;
      border-radius: 50%;
      border: 1px solid #e2e8f0;
    }

    .char-card.active .icon-container {
      background: #e0f2fe;
      border-color: #bae6fd;
    }

    .organ-list {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 4px;
      margin-bottom: 10px;
    }

    .organ-pill {
      font-size: 11px;
      font-weight: 600;
      color: #334155;
      background: #f1f5f9;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 3px 7px;
    }

    .char-card.active .organ-pill {
      background: #ffffff;
      border-color: #cbd5e1;
      color: #0f172a;
    }

    .role-note {
      font-size: 12px;
      font-weight: 500;
      color: #475569;
      line-height: 1.35;
      padding-top: 6px;
      border-top: 1px dashed #e2e8f0;
      width: 100%;
    }

    .prompt-hint {
      margin-top: 10px;
      font-size: 11px;
      font-weight: 500;
      color: #64748b;
      display: flex;
      align-items: center;
      gap: 4px;
    }
  </style>
</head>
<body>

  <div class="header-section">
    <h1 class="title">Primary Characteristics: Direct Reproductive Role</h1>
    <span class="badge-tag">#Direct Reproduction</span>
  </div>

  <div class="cards-grid">
    
    <div class="char-card active" id="cardFemale" tabindex="0" role="button" aria-pressed="true">
      <div class="card-label">Biological Female</div>
      <div class="icon-container">
        
        <svg width="46" height="46" viewBox="0 0 46 46" fill="none">
          <circle cx="23" cy="23" r="19" stroke="#f472b6" stroke-width="2" stroke-dasharray="3 2" fill="#fdf2f8"/>
          <circle cx="23" cy="23" r="14" fill="#ec4899" fill-opacity="0.15" stroke="#db2777" stroke-width="1.5"/>
          <circle cx="23" cy="23" r="6" fill="#db2777"/>
          <circle cx="21.5" cy="21.5" r="1.5" fill="#ffffff"/>
        </svg>
      </div>
      <div class="organ-list">
        <span class="organ-pill">Ovaries</span>
        <span class="organ-pill">Uterus</span>
        <span class="organ-pill">Vagina</span>
      </div>
      <div class="role-note">Matures to release eggs &amp; support pregnancy</div>
    </div>

    
    <div class="char-card" id="cardMale" tabindex="0" role="button" aria-pressed="false">
      <div class="card-label">Biological Male</div>
      <div class="icon-container">
        
        <svg width="46" height="46" viewBox="0 0 46 46" fill="none">
          
          <path d="M28 20 C 33 16, 37 26, 42 22" stroke="#0284c7" stroke-width="2" stroke-linecap="round" fill="none"/>
          
          <ellipse cx="18" cy="23" rx="10" ry="7" fill="#0ea5e9" fill-opacity="0.2" stroke="#0284c7" stroke-width="1.5"/>
          <circle cx="16" cy="23" r="3.5" fill="#0284c7"/>
          <circle cx="15" cy="22" r="1" fill="#ffffff"/>
        </svg>
      </div>
      <div class="organ-list">
        <span class="organ-pill">Testes</span>
        <span class="organ-pill">Penis</span>
        <span class="organ-pill">Scrotum</span>
      </div>
      <div class="role-note">Matures to produce &amp; deliver sperm</div>
    </div>
  </div>

  <div class="prompt-hint">
    <span>✦ Tap either card to compare</span>
  </div>

  <script>
    const cardFemale = document.getElementById('cardFemale');
    const cardMale = document.getElementById('cardMale');

    function setActive(selected, other) {
      selected.classList.add('active');
      selected.setAttribute('aria-pressed', 'true');
      other.classList.remove('active');
      other.setAttribute('aria-pressed', 'false');
    }

    cardFemale.addEventListener('click', () => setActive(cardFemale, cardMale));
    cardMale.addEventListener('click', () => setActive(cardMale, cardFemale));

    cardFemale.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' || e.key === ' ') {
        e.preventDefault();
        setActive(cardFemale, cardMale);
      }
    });

    cardMale.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' || e.key === ' ') {
        e.preventDefault();
        setActive(cardMale, cardFemale);
      }
    });
  </script>
</body>
</html>

Biological Changes in Puberty: Hormones and Growth Spurts

<!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;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      padding: 12px;
      background: #f8fafc;
      color: #1e293b;
    }

    .header-area {
      text-align: center;
      margin-bottom: 12px;
    }

    .title {
      font-size: 17px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: -0.01em;
    }

    /* Filter Controls */
    .filter-bar {
      display: flex;
      justify-content: center;
      gap: 6px;
      margin-top: 8px;
      flex-wrap: wrap;
    }

    .filter-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 4px 10px;
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .filter-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 4px rgba(2, 132, 199, 0.25);
    }

    /* Grid Layout */
    .columns-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 10px;
    }

    @media (max-width: 580px) {
      .columns-grid {
        grid-template-columns: 1fr;
        gap: 12px;
      }
    }

    .category-col {
      background: #ffffff;
      border-radius: 12px;
      border: 1px solid #e2e8f0;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 8px;
      transition: opacity 0.25s ease, transform 0.25s ease;
    }

    .category-col.dimmed {
      opacity: 0.35;
      filter: grayscale(40%);
    }

    /* Column Headers & Pills */
    .col-header {
      display: flex;
      align-items: center;
      justify-content: center;
      padding-bottom: 4px;
      border-bottom: 1px solid #f1f5f9;
    }

    .category-pill {
      display: inline-flex;
      align-items: center;
      gap: 4px;
      padding: 4px 10px;
      border-radius: 16px;
      font-size: 12px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.03em;
    }

    .pill-shared {
      background: #f3e8ff;
      color: #7e22ce;
      border: 1px solid #e9d5ff;
    }

    .pill-female {
      background: #fdf2f8;
      color: #be185d;
      border: 1px solid #fbcfe8;
    }

    .pill-male {
      background: #eff6ff;
      color: #1d4ed8;
      border: 1px solid #bfdbfe;
    }

    /* Item Tiles */
    .item-tile {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 10px;
      display: flex;
      align-items: center;
      gap: 8px;
      cursor: pointer;
      transition: background 0.15s ease, border-color 0.15s ease;
    }

    .item-tile:hover, .item-tile.selected {
      background: #ffffff;
      border-color: #94a3b8;
      box-shadow: 0 2px 5px rgba(0,0,0,0.04);
    }

    .tile-icon {
      font-size: 18px;
      width: 28px;
      height: 28px;
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-shrink: 0;
    }

    .icon-shared { background: #f5f3ff; }
    .icon-female { background: #fff1f2; }
    .icon-male { background: #f0f9ff; }

    .tile-content {
      display: flex;
      flex-direction: column;
    }

    .tile-title {
      font-size: 13px;
      font-weight: 600;
      color: #1e293b;
      line-height: 1.25;
    }

    .tile-sub {
      font-size: 11px;
      color: #64748b;
      margin-top: 1px;
    }
  </style>
</head>
<body>

  <div class="header-area">
    <h1 class="title">Secondary Sexual Characteristics</h1>
    <div class="filter-bar">
      <button class="filter-btn active" data-filter="all">All Changes</button>
      <button class="filter-btn" data-filter="shared">Shared</button>
      <button class="filter-btn" data-filter="female">Typically Female</button>
      <button class="filter-btn" data-filter="male">Typically Male</button>
    </div>
  </div>

  <div class="columns-grid">

    
    <div class="category-col" data-cat="shared">
      <div class="col-header">
        <span class="category-pill pill-shared">✦ Shared Changes</span>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-shared">📏</div>
        <div class="tile-content">
          <div class="tile-title">Rapid Growth Spurt</div>
          <div class="tile-sub">Height & bone length</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-shared">🌿</div>
        <div class="tile-content">
          <div class="tile-title">Pubic & Underarm Hair</div>
          <div class="tile-sub">Follicle maturation</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-shared">💧</div>
        <div class="tile-content">
          <div class="tile-title">Sweat & Oil Production</div>
          <div class="tile-sub">Sebaceous glands active</div>
        </div>
      </div>
    </div>

    
    <div class="category-col" data-cat="female">
      <div class="col-header">
        <span class="category-pill pill-female">♀ Typically Female</span>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-female">🌸</div>
        <div class="tile-content">
          <div class="tile-title">Breast Development</div>
          <div class="tile-sub">Glandular tissue growth</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-female">⌛</div>
        <div class="tile-content">
          <div class="tile-title">Widening of Hips</div>
          <div class="tile-sub">Pelvic bone expansion</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-female">✨</div>
        <div class="tile-content">
          <div class="tile-title">Fat Redistribution</div>
          <div class="tile-sub">Thighs, hips & chest</div>
        </div>
      </div>
    </div>

    
    <div class="category-col" data-cat="male">
      <div class="col-header">
        <span class="category-pill pill-male">♂ Typically Male</span>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-male">🗣️</div>
        <div class="tile-content">
          <div class="tile-title">Deepening Voice</div>
          <div class="tile-sub">Larynx & cord growth</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-male">🧔</div>
        <div class="tile-content">
          <div class="tile-title">Facial & Chest Hair</div>
          <div class="tile-sub">Androgen response</div>
        </div>
      </div>

      <div class="item-tile">
        <div class="tile-icon icon-male">💪</div>
        <div class="tile-content">
          <div class="tile-title">Broadening Shoulders</div>
          <div class="tile-sub">Upper-body muscle mass</div>
        </div>
      </div>
    </div>

  </div>

  <script>
    const filterButtons = document.querySelectorAll('.filter-btn');
    const cols = document.querySelectorAll('.category-col');
    const tiles = document.querySelectorAll('.item-tile');

    filterButtons.forEach(btn => {
      btn.addEventListener('click', () => {
        const filter = btn.dataset.filter;
        
        filterButtons.forEach(b => b.classList.remove('active'));
        btn.classList.add('active');

        cols.forEach(col => {
          if (filter === 'all' || col.dataset.cat === filter) {
            col.classList.remove('dimmed');
          } else {
            col.classList.add('dimmed');
          }
        });
      });
    });

    tiles.forEach(tile => {
      tile.addEventListener('click', () => {
        tiles.forEach(t => t.classList.remove('selected'));
        tile.classList.add('selected');
      });
    });
  </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 {
      width: 100%;
      min-height: 100%;
      background: #ffffff;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 8px 10px;
      gap: 8px;
      user-select: none;
      -webkit-user-select: none;
      overflow-x: hidden;
    }
    .stepper-nav {
      display: flex;
      gap: 6px;
      width: 100%;
      max-width: 440px;
      justify-content: center;
    }
    .step-btn {
      flex: 1;
      padding: 7px 4px;
      font-size: 11px;
      font-weight: 600;
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      color: #475569;
      cursor: pointer;
      text-align: center;
      transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
      white-space: nowrap;
    }
    .step-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }
    .step-btn.active {
      background: #e0f2fe;
      color: #0369a1;
      border-color: #38bdf8;
      box-shadow: 0 1px 2px rgba(2, 132, 199, 0.1);
    }
    .stage {
      position: relative;
      width: 100%;
      max-width: 440px;
      height: 250px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .bone-svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }
    /* SVG styles and transitions */
    .plate-active {
      transition: fill 0.4s ease, stroke 0.4s ease, height 0.4s ease, filter 0.4s ease;
    }
    .dynamic-line {
      transition: y2 0.5s ease, cy 0.5s ease;
    }
    .callout-overlay {
      opacity: 0;
      transition: opacity 0.3s ease, transform 0.3s ease;
      transform: translateY(3px);
      pointer-events: none;
    }
    .callout-overlay.show {
      opacity: 1;
      transform: translateY(0);
      pointer-events: auto;
    }
    .growth-arrow {
      opacity: 0;
      transition: opacity 0.3s ease;
      pointer-events: none;
    }
    .growth-arrow.show {
      opacity: 1;
      pointer-events: auto;
    }
    .badge-title {
      font-size: 11px;
      font-weight: 700;
    }
    .badge-sub {
      font-size: 9.5px;
      fill: #475569;
      font-weight: 500;
    }
    .controls {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 2px;
    }
    .play-btn {
      width: 30px;
      height: 30px;
      border-radius: 50%;
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      font-size: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: background 0.2s ease, border-color 0.2s ease;
    }
    .play-btn:hover {
      background: #e2e8f0;
      border-color: #94a3b8;
    }
    .dots {
      display: flex;
      gap: 6px;
      align-items: center;
    }
    .dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: background 0.25s ease;
    }
    .dot.active {
      background: #0284c7;
    }

    @media (max-width: 360px) {
      body {
        padding: 6px 4px;
        gap: 6px;
      }
      .step-btn {
        font-size: 10px;
        padding: 6px 2px;
      }
      .stage {
        height: 235px;
      }
    }
  </style>
</head>
<body>

  
  <div class="stepper-nav">
    <button class="step-btn active" id="btn0">1. Hormone Surge</button>
    <button class="step-btn" id="btn1">2. Peak Velocity</button>
    <button class="step-btn" id="btn2">3. Plate Fusion</button>
  </div>

  
  <div class="stage">
    <svg class="bone-svg" viewBox="0 0 400 240">
      <defs>
        
        <linearGradient id="boneGrad" x1="0" y1="0" x2="1" y2="0">
          <stop offset="0%" stop-color="#fffdf5"/>
          <stop offset="50%" stop-color="#fef3c7"/>
          <stop offset="100%" stop-color="#fde68a"/>
        </linearGradient>
        <filter id="glow" x="-20%" y="-20%" width="140%" height="140%">
          <feDropShadow dx="0" dy="0" stdDeviation="2.5" flood-color="#38bdf8" flood-opacity="0.7"/>
        </filter>
      </defs>

      
      <line x1="120" y1="36" x2="280" y2="36" stroke="#e2e8f0" stroke-width="1.5" stroke-dasharray="3,3"/>
      <line x1="120" y1="204" x2="280" y2="204" stroke="#e2e8f0" stroke-width="1.5" stroke-dasharray="3,3"/>

      
      
      <rect id="boneShaft" x="186" y="56" width="28" height="128" rx="4" fill="url(#boneGrad)" stroke="#d97706" stroke-width="1.5" style="transition: all 0.5s ease;"/>

      
      <g id="topHead" style="transition: transform 0.5s ease;">
        <path d="M 176 56 C 160 42, 170 18, 200 18 C 230 18, 240 42, 224 56 Z" fill="url(#boneGrad)" stroke="#d97706" stroke-width="1.5"/>
        
        <rect id="plateTop" class="plate-active" x="180" y="52" width="40" height="8" rx="3" fill="#38bdf8" stroke="#0284c7" stroke-width="1.5" style="filter: url(#glow);"/>
      </g>

      
      <g id="bottomHead" style="transition: transform 0.5s ease;">
        <path d="M 176 184 C 160 198, 170 222, 200 222 C 230 222, 240 198, 224 184 Z" fill="url(#boneGrad)" stroke="#d97706" stroke-width="1.5"/>
        
        <rect id="plateBottom" class="plate-active" x="180" y="180" width="40" height="8" rx="3" fill="#38bdf8" stroke="#0284c7" stroke-width="1.5" style="filter: url(#glow);"/>
      </g>

      
      <g>
        <rect x="14" y="38" width="138" height="38" rx="6" fill="#f0f9ff" stroke="#bae6fd" stroke-width="1.5"/>
        <text x="83" y="54" text-anchor="middle" class="badge-title" fill="#0369a1">Epiphyseal Plate</text>
        <text x="83" y="68" text-anchor="middle" class="badge-sub">Cartilage Growth Zone</text>
        
        
        <line id="plateLine" x1="152" y1="56" x2="180" y2="56" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="3,2" style="transition: all 0.5s ease;"/>
        <circle id="plateLineDot" cx="180" cy="56" r="3" fill="#0284c7" style="transition: all 0.5s ease;"/>
      </g>

      
      <g id="step1Visual" class="callout-overlay show">
        <g>
          <rect x="248" y="36" width="140" height="42" rx="6" fill="#ecfdf5" stroke="#a7f3d0" stroke-width="1.5"/>
          <text x="318" y="52" text-anchor="middle" class="badge-title" fill="#065f46">✦ Hormonal Signal</text>
          <text x="318" y="67" text-anchor="middle" class="badge-sub">GH • IGF-1 • Sex Steroids</text>
          
          <line id="hormoneLine" x1="248" y1="56" x2="220" y2="56" stroke="#10b981" stroke-width="1.5" stroke-dasharray="3,2" style="transition: all 0.5s ease;"/>
          <circle id="hormoneLineDot" cx="220" cy="56" r="3" fill="#10b981" style="transition: all 0.5s ease;"/>
        </g>
      </g>

      
      <g id="step2Visual" class="growth-arrow">
        
        <path d="M 200 32 L 200 6 M 195 12 L 200 6 L 205 12" stroke="#0284c7" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"/>
        
        <path d="M 200 208 L 200 234 M 195 228 L 200 234 L 205 228" stroke="#0284c7" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"/>
        
        <g>
          <rect x="248" y="100" width="140" height="42" rx="6" fill="#e0f2fe" stroke="#7dd3fc" stroke-width="1.5"/>
          <text x="318" y="116" text-anchor="middle" class="badge-title" fill="#0369a1">⬆ Peak Velocity (PHV)</text>
          <text x="318" y="131" text-anchor="middle" class="badge-sub">Rapid Vertical Elongation</text>
          <line x1="248" y1="121" x2="216" y2="121" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="3,2"/>
          <circle cx="216" cy="121" r="3" fill="#0284c7"/>
        </g>
      </g>

      
      <g id="step3Visual" class="callout-overlay">
        <g>
          <rect x="248" y="100" width="140" height="42" rx="6" fill="#fef2f2" stroke="#fecaca" stroke-width="1.5"/>
          <text x="318" y="116" text-anchor="middle" class="badge-title" fill="#991b1b">🔒 Complete Fusion</text>
          <text x="318" y="131" text-anchor="middle" class="badge-sub">Cartilage Solidifies to Bone</text>
          <line x1="248" y1="121" x2="216" y2="121" stroke="#ef4444" stroke-width="1.5" stroke-dasharray="3,2"/>
          <circle cx="216" cy="121" r="3" fill="#ef4444"/>
        </g>
      </g>
    </svg>
  </div>

  
  <div class="controls">
    <button class="play-btn" id="playBtn" aria-label="Play/Pause">⏸</button>
    <div class="dots">
      <div class="dot active" id="dot0"></div>
      <div class="dot" id="dot1"></div>
      <div class="dot" id="dot2"></div>
    </div>
  </div>

  <script>
    const btns = [
      document.getElementById('btn0'),
      document.getElementById('btn1'),
      document.getElementById('btn2')
    ];
    const dots = [
      document.getElementById('dot0'),
      document.getElementById('dot1'),
      document.getElementById('dot2')
    ];
    const step1 = document.getElementById('step1Visual');
    const step2 = document.getElementById('step2Visual');
    const step3 = document.getElementById('step3Visual');
    
    const plateTop = document.getElementById('plateTop');
    const plateBottom = document.getElementById('plateBottom');
    const topHead = document.getElementById('topHead');
    const bottomHead = document.getElementById('bottomHead');
    const boneShaft = document.getElementById('boneShaft');
    const plateLine = document.getElementById('plateLine');
    const plateLineDot = document.getElementById('plateLineDot');
    const hormoneLine = document.getElementById('hormoneLine');
    const hormoneLineDot = document.getElementById('hormoneLineDot');
    const playBtn = document.getElementById('playBtn');

    function applyStep(index) {
      btns.forEach((b, i) => b.classList.toggle('active', i === index));
      dots.forEach((d, i) => d.classList.toggle('active', i === index));

      if (index === 0) {
        // Step 1: Hormonal stimulation of cartilage cells
        step1.setAttribute('class', 'callout-overlay show');
        step2.setAttribute('class', 'growth-arrow');
        step3.setAttribute('class', 'callout-overlay');

        topHead.style.transform = 'translateY(0px)';
        bottomHead.style.transform = 'translateY(0px)';
        boneShaft.setAttribute('y', '56');
        boneShaft.setAttribute('height', '128');

        // Epiphyseal plate active and glowing blue
        plateTop.setAttribute('fill', '#38bdf8');
        plateTop.setAttribute('stroke', '#0284c7');
        plateTop.setAttribute('height', '8');
        plateTop.style.filter = 'url(#glow)';

        plateBottom.setAttribute('fill', '#38bdf8');
        plateBottom.setAttribute('stroke', '#0284c7');
        plateBottom.setAttribute('height', '8');
        plateBottom.style.filter = 'url(#glow)';

        // Align pointer line directly to growth plate center
        plateLine.setAttribute('y2', '56');
        plateLineDot.setAttribute('cy', '56');
        hormoneLine.setAttribute('y2', '56');
        hormoneLineDot.setAttribute('cy', '56');
      } else if (index === 1) {
        // Step 2: Peak Height Velocity (Longitudinal growth)
        step1.setAttribute('class', 'callout-overlay');
        step2.setAttribute('class', 'growth-arrow show');
        step3.setAttribute('class', 'callout-overlay');

        topHead.style.transform = 'translateY(-16px)';
        bottomHead.style.transform = 'translateY(16px)';
        boneShaft.setAttribute('y', '40');
        boneShaft.setAttribute('height', '160');

        plateTop.setAttribute('fill', '#0284c7');
        plateTop.setAttribute('stroke', '#0369a1');
        plateTop.setAttribute('height', '10');
        plateTop.style.filter = 'url(#glow)';

        plateBottom.setAttribute('fill', '#0284c7');
        plateBottom.setAttribute('stroke', '#0369a1');
        plateBottom.setAttribute('height', '10');
        plateBottom.style.filter = 'url(#glow)';

        // Track growth plate as it translates upward
        plateLine.setAttribute('y2', '41');
        plateLineDot.setAttribute('cy', '41');
      } else if (index === 2) {
        // Step 3: Epiphyseal Plate Fusion (Calcification ends vertical growth)
        step1.setAttribute('class', 'callout-overlay');
        step2.setAttribute('class', 'growth-arrow');
        step3.setAttribute('class', 'callout-overlay show');

        topHead.style.transform = 'translateY(-16px)';
        bottomHead.style.transform = 'translateY(16px)';
        boneShaft.setAttribute('y', '40');
        boneShaft.setAttribute('height', '160');

        // Growth plate solidifies into a thin epiphyseal line
        plateTop.setAttribute('fill', '#fde047');
        plateTop.setAttribute('stroke', '#d97706');
        plateTop.setAttribute('height', '2.5');
        plateTop.style.filter = 'none';

        plateBottom.setAttribute('fill', '#fde047');
        plateBottom.setAttribute('stroke', '#d97706');
        plateBottom.setAttribute('height', '2.5');
        plateBottom.style.filter = 'none';

        // Track hardened epiphyseal line
        plateLine.setAttribute('y2', '41');
        plateLineDot.setAttribute('cy', '41');
      }
    }

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

    function startTimer() {
      if (timer) clearInterval(timer);
      timer = setInterval(() => {
        currentIndex = (currentIndex + 1) % 3;
        applyStep(currentIndex);
      }, 3600);
    }

    function stopTimer() {
      if (timer) clearInterval(timer);
      timer = null;
    }

    function goTo(idx) {
      currentIndex = idx;
      applyStep(currentIndex);
      if (isPlaying) {
        startTimer();
      }
    }

    btns.forEach((btn, idx) => {
      btn.addEventListener('click', () => goTo(idx));
    });

    dots.forEach((dot, idx) => {
      dot.addEventListener('click', () => goTo(idx));
    });

    playBtn.addEventListener('click', () => {
      isPlaying = !isPlaying;
      playBtn.textContent = isPlaying ? '⏸' : '▶';
      if (isPlaying) {
        startTimer();
      } else {
        stopTimer();
      }
    });

    // Initialize
    applyStep(0);
    startTimer();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      user-select: none;
    }

    .diagram-area {
      position: relative;
      width: 100%;
      max-width: 520px;
      height: 380px;
      margin: 0 auto;
    }

    /* SVG Arrows Layer */
    .flow-svg {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      z-index: 1;
      pointer-events: none;
    }

    .flow-line {
      stroke: #94a3b8;
      stroke-width: 2.5;
      stroke-dasharray: 6, 6;
      fill: none;
      transition: stroke 0.3s ease;
    }

    .pulse-dot {
      fill: #64748b;
      opacity: 0;
      transition: opacity 0.3s ease;
    }

    .active-flow .flow-line-left {
      stroke: #f472b6;
      animation: dashMove 1.5s linear infinite;
    }
    .active-flow .flow-line-right {
      stroke: #38bdf8;
      animation: dashMove 1.5s linear infinite;
    }
    .active-flow .pulse-dot {
      opacity: 1;
    }

    @keyframes dashMove {
      to { stroke-dashoffset: -24; }
    }

    /* Node Cards */
    .node {
      position: absolute;
      z-index: 2;
      border-radius: 12px;
      padding: 8px 12px;
      text-align: center;
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      transition: all 0.3s ease;
      box-shadow: 0 2px 6px rgba(0,0,0,0.04);
    }

    .node-title {
      font-size: 13px;
      font-weight: 700;
      line-height: 1.2;
    }

    .node-sub {
      font-size: 11px;
      font-weight: 600;
      margin-top: 2px;
      opacity: 0.85;
    }

    /* Top Node */
    .node-brain {
      top: 8px;
      left: 50%;
      transform: translateX(-50%);
      width: 170px;
      background: #f8fafc;
    }

    .node-signal {
      top: 88px;
      left: 50%;
      transform: translateX(-50%);
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      background: #ffffff;
      padding: 3px 8px;
      border-radius: 10px;
      border: 1px dashed #cbd5e1;
    }

    /* Left Branch (Female) */
    .node-female {
      left: 2%;
      width: 44%;
      border-color: #fbcfe8;
      background: #fff;
    }
    .node-ovaries {
      top: 136px;
    }
    .node-estrogen {
      top: 216px;
      background: #fce7f3;
      color: #831843;
    }
    .node-female-changes {
      top: 298px;
      background: #fdf2f8;
      border: 1.5px dashed #f472b6;
    }

    /* Right Branch (Male) */
    .node-male {
      right: 2%;
      width: 44%;
      border-color: #bae6fd;
      background: #fff;
    }
    .node-testes {
      top: 136px;
    }
    .node-testosterone {
      top: 216px;
      background: #e0f2fe;
      color: #0369a1;
    }
    .node-male-changes {
      top: 298px;
      background: #f0f9ff;
      border: 1.5px dashed #38bdf8;
    }

    /* Active Highlight States */
    .highlight-top {
      border-color: #818cf8;
      box-shadow: 0 0 0 3px rgba(129, 140, 248, 0.25);
    }
    .highlight-female {
      border-color: #ec4899;
      box-shadow: 0 0 0 3px rgba(236, 72, 153, 0.25);
    }
    .highlight-male {
      border-color: #0284c7;
      box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.25);
    }

    /* Controls Bar */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-top: 6px;
      width: 100%;
      max-width: 520px;
    }

    .btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      padding: 6px 14px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: all 0.2s ease;
    }

    .btn:active {
      background: #f1f5f9;
    }

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

    .dot-nav {
      display: flex;
      gap: 6px;
      margin: 0 6px;
    }

    .step-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #e2e8f0;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .step-dot.active {
      background: #1e2945;
      transform: scale(1.15);
    }

    .badge-icon {
      font-size: 14px;
      margin-right: 2px;
      vertical-align: -1px;
    }
  </style>
</head>
<body>

  <div class="diagram-area" id="diagram">
    
    <svg class="flow-svg" viewBox="0 0 400 380" preserveAspectRatio="none">
      <defs>
        <marker id="arrow-pink" viewBox="0 0 10 10" refX="5" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#f472b6"/>
        </marker>
        <marker id="arrow-blue" viewBox="0 0 10 10" refX="5" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#38bdf8"/>
        </marker>
      </defs>

      
      <path class="flow-line flow-line-left" d="M 200 48 C 200 95, 96 95, 96 136" marker-end="url(#arrow-pink)"/>
      
      <path class="flow-line flow-line-right" d="M 200 48 C 200 95, 304 95, 304 136" marker-end="url(#arrow-blue)"/>

      
      <path class="flow-line flow-line-left" d="M 96 178 L 96 214" marker-end="url(#arrow-pink)"/>
      
      <path class="flow-line flow-line-left" d="M 96 256 L 96 296" marker-end="url(#arrow-pink)"/>

      
      <path class="flow-line flow-line-right" d="M 304 178 L 304 214" marker-end="url(#arrow-blue)"/>
      
      <path class="flow-line flow-line-right" d="M 304 256 L 304 296" marker-end="url(#arrow-blue)"/>
    </svg>

    
    <div class="node node-brain" id="nodePituitary">
      <div class="node-title">🧠 Pituitary Gland</div>
      <div class="node-sub">Brain Control Center</div>
    </div>

    <div class="node-signal">Hormone Signals ↓</div>

    
    <div class="node node-female node-ovaries" id="nodeOvaries">
      <div class="node-title"><span class="badge-icon">🌸</span>Ovaries</div>
    </div>

    <div class="node node-female node-estrogen" id="nodeEstrogen">
      <div class="node-title">Estrogen</div>
    </div>

    <div class="node node-female node-female-changes" id="nodeFemaleChanges">
      <div class="node-title">Growth & Maturation</div>
    </div>

    
    <div class="node node-male node-testes" id="nodeTestes">
      <div class="node-title"><span class="badge-icon">⚡</span>Testes</div>
    </div>

    <div class="node node-male node-testosterone" id="nodeTestosterone">
      <div class="node-title">Testosterone</div>
    </div>

    <div class="node node-male node-male-changes" id="nodeMaleChanges">
      <div class="node-title">Growth & Maturation</div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn" id="playBtn">⏸ Pause</button>
    <div class="dot-nav">
      <div class="step-dot active" data-step="0" title="Step 1"></div>
      <div class="step-dot" data-step="1" title="Step 2"></div>
      <div class="step-dot" data-step="2" title="Step 3"></div>
    </div>
    <button class="btn" id="nextBtn">Next →</button>
  </div>

  <script>
    const diagram = document.getElementById('diagram');
    const dots = document.querySelectorAll('.step-dot');
    const playBtn = document.getElementById('playBtn');
    const nextBtn = document.getElementById('nextBtn');

    const topNode = document.getElementById('nodePituitary');
    const ovariesNode = document.getElementById('nodeOvaries');
    const testesNode = document.getElementById('nodeTestes');
    const estrogenNode = document.getElementById('nodeEstrogen');
    const testosterNode = document.getElementById('nodeTestosterone');
    const fChangesNode = document.getElementById('nodeFemaleChanges');
    const mChangesNode = document.getElementById('nodeMaleChanges');

    let currentStep = 0;
    let isPlaying = true;
    let intervalId = null;

    function applyStep(step) {
      currentStep = step;
      diagram.classList.add('active-flow');

      // Clear highlights
      [topNode, ovariesNode, testesNode, estrogenNode, testosterNode, fChangesNode, mChangesNode].forEach(el => {
        el.classList.remove('highlight-top', 'highlight-female', 'highlight-male');
      });

      dots.forEach((dot, idx) => {
        dot.classList.toggle('active', idx === step);
      });

      if (step === 0) {
        topNode.classList.add('highlight-top');
      } else if (step === 1) {
        ovariesNode.classList.add('highlight-female');
        estrogenNode.classList.add('highlight-female');
        testesNode.classList.add('highlight-male');
        testosterNode.classList.add('highlight-male');
      } else if (step === 2) {
        fChangesNode.classList.add('highlight-female');
        mChangesNode.classList.add('highlight-male');
      }
    }

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

    function startAutoPlay() {
      if (intervalId) clearInterval(intervalId);
      intervalId = setInterval(nextStep, 3200);
      isPlaying = true;
      playBtn.textContent = '⏸ Pause';
    }

    function stopAutoPlay() {
      if (intervalId) clearInterval(intervalId);
      intervalId = null;
      isPlaying = false;
      playBtn.textContent = '▶ Play';
    }

    playBtn.addEventListener('click', () => {
      if (isPlaying) stopAutoPlay();
      else { nextStep(); startAutoPlay(); }
    });

    nextBtn.addEventListener('click', () => {
      nextStep();
      if (isPlaying) startAutoPlay();
    });

    dots.forEach((dot, index) => {
      dot.addEventListener('click', () => {
        applyStep(index);
        if (isPlaying) startAutoPlay();
      });
    });

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

Sistema nervoso: estrutura e funções básicas

Coordenação das ações motoras e sensoriais

Neurônios: os mensageiros do sistema nervoso

A visão: como o olho capta imagens

Interpretação de imagens pelo cérebro

Defeitos da visão: miopia e hipermetropia

Lentes corretivas: como escolher a lente certa

Sistemas muscular e ósseo: a sustentação do corpo

Movimentação dos animais: integração dos sistemas nervoso, muscular e ósseo

Substâncias psicoativas e o sistema nervoso

science

Corpo humano: coordenação e movimentação

Contaminantes atmosféricos: material particulado y gases tóxicos

Enfermedades respiratorias asociadas a la calidad del aire

Contaminación química del suelo: pesticidas y metales pesados

Bioacumulación y biomagnificación en las redes tróficas

Gestión inadecuada de residuos sólidos: lixiviados y vectores

El problema de los microplásticos en ecosistemas y alimentos

Contaminación acústica y efectos en el sistema auditivo y nervioso

Contaminación lumínica y alteración de ritmos circadianos

Calidad del agua potable y enfermedades gastrointestinales

Monitoreo ambiental participativo en la escuela y barrio

Factores de contaminación ambiental y salud humana

Endocrine System and Sex Hormone Action

Human Reproductive Systems and the Menstrual Cycle

Pathogens and Infectious Disease Transmission

The Human Immune System and Body Defenses

Vaccination Mechanisms and Herd Immunity

Poor Eating Habits and Physical Inactivity as Causes of Disease

Physiological Impacts of Alcohol and Tobacco

Psychoactive Substances and Nervous System Effects

Human Growth, Puberty, and Health Science

Macronutrientes: carbohidratos, proteínas y lípidos

Micronutrientes: vitaminas y minerales esenciales

El plato saludable de la familia colombiana: proporciones y grupos

Dietas tradicionales de las regiones naturales de Colombia

Disponibilidad agrícola, estacionalidad y seguridad alimentaria

Alimentos ultraprocesados y rotulado nutricional frontal

Consecuencias de la malnutrición: desnutrición y obesidad

Conservación de alimentos: métodos térmicos, químicos y en frío

Huertas escolares y caseras: soberanía alimentaria local

Balance energético: gasto calórico y requerimientos por edad

Alimentación balanceada y recursos nutricionales

Factores biológicos, psicológicos y culturales de la sexualidad

Cambios físicos y hormonales en la pubertad

Anatomía y fisiología del sistema reproductor femenino

Anatomía y fisiología del sistema reproductor masculino

Fecundación, embarazo y etapas del desarrollo embrionario

Maternidad y paternidad responsables: implicaciones de vida

Embarazo en la adolescencia: riesgos biológicos y proyecto de vida

Comunicación asertiva, consentimiento y autonomía corporal

Higiene y autocuidado en la pubertad

Redes de apoyo institucional y orientación juvenil en salud sexual

Sexualidad humana, responsabilidad y salud reproductiva

Agentes infecciosos: virus, bacterias, hongos y parásitos

Vías de transmisión: aérea, hídrica, contacto y vectorial

Enfermedades transmitidas por vectores: dengue, zika y chikungunya

Infecciones respiratorias agudas y mecanismos de barrera

El sistema inmunológico: defensas naturales del cuerpo

Vacunación e inmunidad colectiva en las comunidades

Uso responsable de antibióticos y resistencia bacteriana en el entorno

Infecciones de transmisión sexual: prevención y cuidado

Saneamiento básico y desinfección de alimentos en el hogar

Vigilancia epidemiológica y alertas tempranas en salud pública

Transmisión de enfermedades y prevención en salud pública

Efectos fisiológicos del consumo excesivo de cafeína y bebidas energizantes

El tabaco y el humo: nicotina, alquitrán y daños pulmonares

Vapeadores y cigarrillos electrónicos: mitos y realidades químicas

El alcohol en el organismo: absorción y efectos en el hígado

El alcohol y el sistema nervioso: coordinación y toma de decisiones

Sustancias psicoactivas: clasificación, estimulantes, depresoras y alucinógenas

OGS.7.LS.3

Aligned learning resources

Related diagrams