<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      width: 100%;
      background: transparent;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      color: #1e2945;
      padding: 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
    }

    .grid-container {
      width: 100%;
      max-width: 520px;
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 12px;
    }

    .card {
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 14px;
      padding: 12px 8px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 140px;
      cursor: pointer;
      position: relative;
      overflow: hidden;
      transition: box-shadow 0.25s ease, border-color 0.25s ease, background-color 0.25s ease;
      -webkit-tap-highlight-color: transparent;
    }

    .card:hover {
      background-color: #fafbfc;
    }

    /* Color Accents */
    .card-air { --accent: #0284c7; --bg-accent: #f0f9ff; }
    .card-contact { --accent: #8b5cf6; --bg-accent: #f5f3ff; }
    .card-food { --accent: #f59e0b; --bg-accent: #fffbeb; }
    .card-vector { --accent: #10b981; --bg-accent: #ecfdf5; }

    .card.active {
      border-color: var(--accent);
      background: var(--bg-accent);
      box-shadow: 0 4px 14px rgba(0, 0, 0, 0.08);
    }

    .card-badge {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: var(--accent);
      margin-bottom: 4px;
    }

    .visual-stage {
      width: 100%;
      height: 64px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    /* Pathway visual elements */
    .entity {
      font-size: 26px;
      line-height: 1;
      z-index: 2;
    }

    .flow-arrow {
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 6px;
      width: 44px;
      height: 16px;
    }

    .flow-line {
      position: absolute;
      width: 100%;
      height: 2px;
      background: #cbd5e1;
      border-radius: 1px;
    }

    .card.active .flow-line {
      background: var(--accent);
    }

    .pathogen {
      position: absolute;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #ef4444;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 8px;
      color: #fff;
      font-weight: bold;
      z-index: 3;
      box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.2);
    }

    /* Animated Pathogen Motion */
    .card.active .pathogen-air {
      animation: driftAir 2s ease-in-out infinite;
    }
    .card.active .pathogen-contact {
      animation: pulseContact 1.6s ease-in-out infinite;
    }
    .card.active .pathogen-water {
      animation: moveIngest 2s ease-in-out infinite;
    }
    .card.active .pathogen-vector {
      animation: moveVector 2s ease-in-out infinite;
    }

    @keyframes driftAir {
      0% { transform: translate(-14px, 4px) scale(0.8); opacity: 0; }
      30% { opacity: 1; }
      80% { opacity: 1; }
      100% { transform: translate(14px, -4px) scale(1.1); opacity: 0; }
    }

    @keyframes pulseContact {
      0%, 100% { transform: scale(0.9); box-shadow: 0 0 0 1px rgba(239, 68, 68, 0.4); }
      50% { transform: scale(1.3); box-shadow: 0 0 0 5px rgba(239, 68, 68, 0.15); }
    }

    @keyframes moveIngest {
      0% { transform: translate(-12px, -6px); opacity: 0; }
      30% { opacity: 1; }
      70% { opacity: 1; }
      100% { transform: translate(12px, 6px); opacity: 0; }
    }

    @keyframes moveVector {
      0% { transform: translate(-12px, 0); opacity: 0; }
      25% { opacity: 1; }
      75% { opacity: 1; }
      100% { transform: translate(14px, 0); opacity: 0; }
    }

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

    @media (max-width: 380px) {
      .grid-container {
        gap: 8px;
      }
      .card {
        padding: 10px 4px 8px;
        min-height: 125px;
      }
      .entity {
        font-size: 22px;
      }
      .flow-arrow {
        width: 32px;
        margin: 0 3px;
      }
      .card-title {
        font-size: 13px;
      }
      .card-badge {
        font-size: 10px;
      }
    }
  </style>
</head>
<body>

  <div class="grid-container">
    
    <div class="card card-air active" onclick="activate(this)">
      <div class="card-badge">1. Respiratory</div>
      <div class="visual-stage">
        <span class="entity">🗣️</span>
        <div class="flow-arrow">
          <div class="flow-line"></div>
          <div class="pathogen pathogen-air"></div>
        </div>
        <span class="entity">👤</span>
      </div>
      <div class="card-title">Airborne</div>
    </div>

    
    <div class="card card-contact active" onclick="activate(this)">
      <div class="card-badge">2. Physical</div>
      <div class="visual-stage">
        <span class="entity">🤝</span>
        <div class="pathogen pathogen-contact" style="position: absolute; top: 27px;"></div>
      </div>
      <div class="card-title">Direct Contact</div>
    </div>

    
    <div class="card card-food active" onclick="activate(this)">
      <div class="card-badge">3. Oral</div>
      <div class="visual-stage">
        <span class="entity">💧</span>
        <div class="flow-arrow">
          <div class="flow-line"></div>
          <div class="pathogen pathogen-water"></div>
        </div>
        <span class="entity">🍗</span>
      </div>
      <div class="card-title">Water &amp; Food</div>
    </div>

    
    <div class="card card-vector active" onclick="activate(this)">
      <div class="card-badge">4. Organism</div>
      <div class="visual-stage">
        <span class="entity">🦟</span>
        <div class="flow-arrow">
          <div class="flow-line"></div>
          <div class="pathogen pathogen-vector"></div>
        </div>
        <span class="entity">👤</span>
      </div>
      <div class="card-title">Vectors</div>
    </div>
  </div>

  <script>
    function activate(el) {
      const cards = document.querySelectorAll('.card');
      const isSingleSelected = document.querySelectorAll('.card.active').length === 1 && el.classList.contains('active');
      
      if (isSingleSelected) {
        // Toggle back to all active if clicked again
        cards.forEach(c => c.classList.add('active'));
      } else {
        cards.forEach(c => c.classList.remove('active'));
        el.classList.add('active');
      }
    }
  </script>
</body>
</html>

Pathogens and Transmission of Communicable Diseases

How Bacteria and Viruses Cause Cellular Damage

Protist and Fungal Pathogens in Animals and Plants

Transmission Pathways: Direct Contact, Droplets, Water, and Vectors

Methods of Controlling Communicable Disease Spread

Exam Practice: Explaining Disease Spread in Animal and Plant Populations

science

Pathogens and Disease Transmission in Animals and Plants

Viral Diseases: Measles Symptoms, Transmission, and Prevention

HIV and AIDS: Transmission, Progression, and Antiretroviral Therapy

Plant Viral Infections: Tobacco Mosaic Virus (TMV)

Bacterial Infections: Salmonella Food Poisoning and Control

Sexually Transmitted Infections: Gonorrhoea Symptoms and Antibiotic Resistance

Plant Fungal Infections: Rose Black Spot Pathology and Treatment

Protist Diseases: Malaria Life Cycle and Mosquito Vector Control

Exam Practice: Comparing Human and Plant Disease Case Studies

Case Studies of Human, Plant, and Sexually Transmitted Diseases

UK-GCSE-SCIENCE-BIO-HDM-02-01

UK-GCSE-SCIENCE-BIO-HDM-02-01

Aligned learning resources

Related diagrams