<!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 {
      width: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e293b;
      display: flex;
      justify-content: center;
      padding: 10px;
    }
    .grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      width: 100%;
      max-width: 620px;
    }
    @media (max-width: 460px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }
    .panel {
      background: #ffffff;
      border-radius: 12px;
      padding: 10px 8px 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      box-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      border: 1px solid #e2e8f0;
    }
    .panel.conductor {
      border-color: #fde047;
      background: linear-gradient(180deg, #fefce8 0%, #ffffff 40%);
    }
    .panel.insulator {
      border-color: #cbd5e1;
      background: linear-gradient(180deg, #f1f5f9 0%, #ffffff 40%);
    }
    .circuit-svg {
      width: 100%;
      height: auto;
      max-height: 205px;
      display: block;
      overflow: visible;
    }
    .badge {
      font-size: 13px;
      font-weight: 700;
      padding: 5px 12px;
      border-radius: 20px;
      margin-top: 6px;
      text-align: center;
      letter-spacing: -0.01em;
    }
    .badge-conductor {
      background: #fef08a;
      color: #854d0e;
      border: 1px solid #facc15;
    }
    .badge-insulator {
      background: #f1f5f9;
      color: #475569;
      border: 1px solid #cbd5e1;
    }

    /* Electric Flow Animation - Smooth & gentle speed */
    .flow-line {
      stroke-dasharray: 6, 8;
      animation: flow 3s linear infinite;
    }
    @keyframes flow {
      from { stroke-dashoffset: 28; }
      to { stroke-dashoffset: 0; }
    }

    /* Glow Pulses */
    .glow-pulse {
      animation: pulse 3s ease-in-out infinite alternate;
    }
    @keyframes pulse {
      0% { opacity: 0.5; transform: scale(0.97); }
      100% { opacity: 0.85; transform: scale(1.03); }
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="panel conductor">
      <svg class="circuit-svg" viewBox="0 0 240 200">
        
        <circle cx="120" cy="38" r="32" fill="#fef08a" opacity="0.45" class="glow-pulse" style="transform-origin: 120px 38px;" />
        <circle cx="120" cy="38" r="22" fill="#fef08a" opacity="0.8" />

        
        <path d="M 98,173 L 49,173 A 14 14 0 0 1 35 159 L 35 52 A 14 14 0 0 1 49 38 L 191 38 A 14 14 0 0 1 205 52 L 205 159 A 14 14 0 0 1 191 173 L 144,173" fill="none" stroke="#64748b" stroke-width="5" stroke-linecap="round" />

        
        <rect x="35" y="38" width="170" height="135" rx="14" fill="none" stroke="#eab308" stroke-width="4" class="flow-line" stroke-linecap="round" />

        
        <g transform="translate(120, 38)">
          
          <circle cx="0" cy="0" r="16" fill="#facc15" stroke="#ca8a04" stroke-width="2" />
          <path d="M-6,3 Q0,-8 6,3" fill="none" stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" />
          
          <rect x="-7" y="16" width="14" height="7" rx="2" fill="#94a3b8" />
          <rect x="-5" y="23" width="10" height="3" rx="1" fill="#64748b" />
          
          <line x1="-22" y1="-14" x2="-14" y2="-8" stroke="#eab308" stroke-width="2.5" stroke-linecap="round" />
          <line x1="0" y1="-26" x2="0" y2="-18" stroke="#eab308" stroke-width="2.5" stroke-linecap="round" />
          <line x1="22" y1="-14" x2="14" y2="-8" stroke="#eab308" stroke-width="2.5" stroke-linecap="round" />
        </g>

        
        <g transform="translate(35, 105)">
          <rect x="-8" y="-18" width="16" height="36" rx="3" fill="#334155" />
          <rect x="-4" y="-22" width="8" height="4" rx="1" fill="#e2e8f0" />
          <rect x="-8" y="-10" width="16" height="10" fill="#ef4444" />
          <text x="0" y="-3" font-size="8" font-weight="900" fill="#ffffff" text-anchor="middle">+</text>
          <text x="0" y="13" font-size="9" font-weight="900" fill="#94a3b8" text-anchor="middle">−</text>
        </g>

        
        <g transform="translate(120, 173)">
          
          <circle cx="-22" cy="0" r="10" fill="#cbd5e1" stroke="#475569" stroke-width="2" />
          <circle cx="-22" cy="0" r="4.5" fill="#fefce8" stroke="#475569" stroke-width="1.5" />
          
          <rect x="-13" y="-3.5" width="37" height="7" rx="2" fill="#cbd5e1" stroke="#475569" stroke-width="1.5" />
          <rect x="12" y="3" width="4" height="6" fill="#cbd5e1" stroke="#475569" stroke-width="1.5" />
          <rect x="20" y="3" width="4" height="8" fill="#cbd5e1" stroke="#475569" stroke-width="1.5" />
          
          <circle cx="-3" cy="0" r="2" fill="#eab308" />
          <circle cx="9" cy="0" r="2" fill="#eab308" />
        </g>
      </svg>
      <div class="badge badge-conductor">Metal Key = Conductor</div>
    </div>

    
    <div class="panel insulator">
      <svg class="circuit-svg" viewBox="0 0 240 200">
        
        <path d="M 94,173 L 49,173 A 14 14 0 0 1 35 159 L 35 52 A 14 14 0 0 1 49 38 L 191 38 A 14 14 0 0 1 205 52 L 205 159 A 14 14 0 0 1 191 173 L 146,173" fill="none" stroke="#94a3b8" stroke-width="5" stroke-linecap="round" />

        
        <path d="M 35 110 L 35 159 A 14 14 0 0 0 49 173 L 92 173" fill="none" stroke="#eab308" stroke-width="4" stroke-dasharray="6 8" stroke-linecap="round" opacity="0.6" />

        
        <g transform="translate(120, 38)">
          <circle cx="0" cy="0" r="16" fill="#e2e8f0" stroke="#94a3b8" stroke-width="2" />
          <path d="M-6,3 Q0,-6 6,3" fill="none" stroke="#94a3b8" stroke-width="2" stroke-linecap="round" />
          
          <rect x="-7" y="16" width="14" height="7" rx="2" fill="#94a3b8" />
          <rect x="-5" y="23" width="10" height="3" rx="1" fill="#64748b" />
        </g>

        
        <g transform="translate(35, 105)">
          <rect x="-8" y="-18" width="16" height="36" rx="3" fill="#334155" />
          <rect x="-4" y="-22" width="8" height="4" rx="1" fill="#e2e8f0" />
          <rect x="-8" y="-10" width="16" height="10" fill="#ef4444" />
          <text x="0" y="-3" font-size="8" font-weight="900" fill="#ffffff" text-anchor="middle">+</text>
          <text x="0" y="13" font-size="9" font-weight="900" fill="#94a3b8" text-anchor="middle">−</text>
        </g>

        
        <g transform="translate(120, 173)">
          
          <polygon points="-26,-8 22,-8 26,8 -22,8" fill="#f472b6" stroke="#db2777" stroke-width="2" stroke-linejoin="round" />
          <polygon points="-22,8 -26,-8 -20,-8 -16,8" fill="#fb7185" opacity="0.4" />
          
          
          <circle cx="-28" cy="0" r="7.5" fill="#ef4444" stroke="#ffffff" stroke-width="1.5" />
          <path d="M-31,-3 L-25,3 M-25,-3 L-31,3" stroke="#ffffff" stroke-width="2" stroke-linecap="round" />
        </g>
      </svg>
      <div class="badge badge-insulator">Rubber Eraser = Insulator</div>
    </div>
  </div>

</body>
</html>

Defining Electrical Conductors and Insulators

<!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>Conductors and Insulators Cutaway</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      width: 100%;
      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: center;
      padding: 12px;
      overflow: hidden;
    }

    .diagram-stage {
      position: relative;
      width: 100%;
      max-width: 580px;
      height: auto;
      aspect-ratio: 4 / 3;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: 100%;
      display: block;
      filter: drop-shadow(0 14px 28px rgba(30, 41, 69, 0.08));
    }

    /* Hotspot interactive buttons */
    .hotspot {
      cursor: pointer;
      outline: none;
    }

    .hotspot rect, .hotspot circle {
      transition: opacity 0.25s ease;
    }

    .hotspot:hover rect {
      opacity: 0.18;
    }

    /* Floating label badges */
    .label-badge {
      position: absolute;
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 10px;
      padding: 8px 12px;
      font-size: 13px;
      line-height: 1.35;
      color: #1e2945;
      box-shadow: 0 4px 14px rgba(0, 0, 0, 0.06);
      transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
      cursor: pointer;
    }

    .label-badge strong {
      display: block;
      font-size: 14px;
      font-weight: 700;
    }

    .badge-insulator {
      top: 10%;
      left: 14%;
    }

    .badge-conductor {
      bottom: 12%;
      right: 12%;
    }

    .badge-insulator.active {
      border-color: #f97316;
      box-shadow: 0 0 0 3px rgba(249, 115, 22, 0.2), 0 6px 16px rgba(249, 115, 22, 0.15);
    }

    .badge-conductor.active {
      border-color: #d97706;
      box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.2), 0 6px 16px rgba(217, 119, 6, 0.15);
    }

    .badge-insulator strong {
      color: #ea580c;
    }

    .badge-conductor strong {
      color: #b45309;
    }

    /* Subtitle / micro text inside badge */
    .badge-sub {
      font-size: 12px;
      color: #64748b;
    }

    /* Electron particle animation */
    @keyframes flowRight {
      0% {
        stroke-dashoffset: 80;
      }
      100% {
        stroke-dashoffset: 0;
      }
    }

    .electron-stream {
      stroke: #fef08a;
      stroke-width: 3.5;
      stroke-linecap: round;
      stroke-dasharray: 4 18;
      animation: flowRight 1.6s linear infinite;
      filter: drop-shadow(0 0 3px #facc15);
    }

    .blocked-indicator {
      transition: opacity 0.3s ease;
    }
  </style>
</head>
<body>

  <div class="diagram-stage">
    <svg viewBox="0 0 600 420" fill="none" xmlns="http://www.w3.org/2000/svg">
      <defs>
        
        <filter id="cableShadow" x="-10%" y="-10%" width="130%" height="150%">
          <feDropShadow dx="0" dy="16" stdDeviation="14" flood-color="#0f172a" flood-opacity="0.12"/>
        </filter>

        
        <linearGradient id="orangeJacket" x1="0" y1="120" x2="0" y2="280" gradientUnits="userSpaceOnUse">
          <stop offset="0%" stop-color="#fdba74"/>
          <stop offset="22%" stop-color="#fb923c"/>
          <stop offset="55%" stop-color="#ea580c"/>
          <stop offset="90%" stop-color="#c2410c"/>
          <stop offset="100%" stop-color="#9a3412"/>
        </linearGradient>

        <linearGradient id="orangeCutRim" x1="260" y1="140" x2="290" y2="260" gradientUnits="userSpaceOnUse">
          <stop offset="0%" stop-color="#fed7aa"/>
          <stop offset="40%" stop-color="#fb923c"/>
          <stop offset="100%" stop-color="#9a3412"/>
        </linearGradient>

        
        <linearGradient id="copperBase" x1="0" y1="160" x2="0" y2="240" gradientUnits="userSpaceOnUse">
          <stop offset="0%" stop-color="#fde047"/>
          <stop offset="15%" stop-color="#fbbf24"/>
          <stop offset="45%" stop-color="#d97706"/>
          <stop offset="80%" stop-color="#b45309"/>
          <stop offset="100%" stop-color="#78350f"/>
        </linearGradient>

        <linearGradient id="copperHighlight" x1="0" y1="0" x2="0" y2="1">
          <stop offset="0%" stop-color="#fffbeb" stop-opacity="0.9"/>
          <stop offset="40%" stop-color="#f59e0b" stop-opacity="0.6"/>
          <stop offset="100%" stop-color="#78350f" stop-opacity="0"/>
        </linearGradient>

        
        <linearGradient id="innerLiner" x1="0" y1="150" x2="0" y2="250" gradientUnits="userSpaceOnUse">
          <stop offset="0%" stop-color="#f8fafc"/>
          <stop offset="50%" stop-color="#cbd5e1"/>
          <stop offset="100%" stop-color="#64748b"/>
        </linearGradient>
      </defs>

      
      <ellipse cx="290" cy="285" rx="210" ry="24" fill="#000000" opacity="0.07" filter="blur(8px)"/>

      
      <g filter="url(#cableShadow)">
        
        
        <path d="M 60 135 L 250 135 Q 260 200 250 265 L 60 265 Q 70 200 60 135 Z" fill="url(#orangeJacket)" />
        
        
        <path d="M 60 148 L 250 148 Q 255 170 252 180 L 60 180 Q 64 165 60 148 Z" fill="#ffffff" opacity="0.25" />

        
        
        <path d="M 250 135 Q 275 200 250 265 Q 235 200 250 135 Z" fill="url(#orangeCutRim)" stroke="#ea580c" stroke-width="1"/>

        
        <path d="M 250 152 L 340 152 Q 352 200 340 248 L 250 248 Q 258 200 250 152 Z" fill="url(#innerLiner)"/>
        
        <path d="M 340 152 Q 354 200 340 248 Q 330 200 340 152 Z" fill="#94a3b8"/>

        
        
        <path d="M 340 162 L 490 162 Q 515 200 490 238 L 340 238 Q 346 200 340 162 Z" fill="url(#copperBase)"/>

        
        
        <path d="M 450 166 Q 500 162 525 152 Q 532 158 522 163 Q 485 174 450 173 Z" fill="url(#copperBase)" stroke="#d97706" stroke-width="0.5"/>
        <path d="M 460 167 Q 500 164 520 155" stroke="#fef08a" stroke-width="1" fill="none" opacity="0.8"/>

        
        <path d="M 460 176 Q 510 176 538 172 Q 542 178 534 182 Q 490 188 460 184 Z" fill="url(#copperBase)" stroke="#d97706" stroke-width="0.5"/>
        <path d="M 465 178 Q 510 178 532 175" stroke="#fef08a" stroke-width="1.2" fill="none" opacity="0.9"/>

        
        <path d="M 470 190 Q 520 193 546 195 Q 548 202 540 204 Q 495 204 470 199 Z" fill="url(#copperBase)" stroke="#d97706" stroke-width="0.5"/>
        <path d="M 472 192 Q 520 195 540 197" stroke="#ffffff" stroke-width="1.3" fill="none" opacity="0.9"/>

        
        <path d="M 460 205 Q 510 212 536 220 Q 530 226 522 224 Q 485 216 460 213 Z" fill="url(#copperBase)" stroke="#d97706" stroke-width="0.5"/>
        <path d="M 465 207 Q 510 214 530 221" stroke="#fef08a" stroke-width="1.2" fill="none" opacity="0.8"/>

        
        <path d="M 450 218 Q 495 230 518 240 Q 512 245 505 243 Q 475 232 450 226 Z" fill="url(#copperBase)" stroke="#d97706" stroke-width="0.5"/>

        
        <path d="M 340 172 L 490 172 L 488 184 L 340 184 Z" fill="url(#copperHighlight)"/>

        
        <g id="currentFlow">
          <path d="M 345 180 L 485 180" class="electron-stream"/>
          <path d="M 345 200 L 515 200" class="electron-stream" style="animation-delay: -0.4s;"/>
          <path d="M 345 220 L 480 220" class="electron-stream" style="animation-delay: -0.8s;"/>
        </g>
      </g>

      
      
      <g id="pointerInsulator">
        <circle cx="180" cy="135" r="4.5" fill="#ea580c"/>
        <circle cx="180" cy="135" r="7" fill="none" stroke="#ea580c" stroke-width="1.5" opacity="0.5"/>
        <path d="M 180 135 L 180 82" stroke="#ea580c" stroke-width="2" stroke-linecap="round"/>
      </g>

      
      <g id="pointerConductor">
        <circle cx="430" cy="238" r="4.5" fill="#d97706"/>
        <circle cx="430" cy="238" r="7" fill="none" stroke="#d97706" stroke-width="1.5" opacity="0.5"/>
        <path d="M 430 238 L 430 328" stroke="#d97706" stroke-width="2" stroke-linecap="round"/>
      </g>

      
      <rect id="hitInsulator" class="hotspot" x="60" y="125" width="200" height="150" fill="#f97316" opacity="0"/>
      <rect id="hitConductor" class="hotspot" x="340" y="145" width="210" height="110" fill="#d97706" opacity="0"/>
    </svg>

    
    <div id="badgeInsulator" class="label-badge badge-insulator active" onclick="selectPart('insulator')">
      <strong>Outer Plastic</strong>
      <span class="badge-sub">Insulator (blocks current)</span>
    </div>

    <div id="badgeConductor" class="label-badge badge-conductor active" onclick="selectPart('conductor')">
      <strong>Inner Copper</strong>
      <span class="badge-sub">Conductor (carries electricity)</span>
    </div>
  </div>

  <script>
    const badgeIns = document.getElementById('badgeInsulator');
    const badgeCond = document.getElementById('badgeConductor');
    const hitIns = document.getElementById('hitInsulator');
    const hitCond = document.getElementById('hitConductor');
    const flow = document.getElementById('currentFlow');

    function selectPart(part) {
      if (part === 'insulator') {
        badgeIns.classList.add('active');
        badgeCond.classList.remove('active');
        flow.style.opacity = '0.35';
      } else if (part === 'conductor') {
        badgeCond.classList.add('active');
        badgeIns.classList.remove('active');
        flow.style.opacity = '1';
      } else {
        badgeIns.classList.add('active');
        badgeCond.classList.add('active');
        flow.style.opacity = '1';
      }
    }

    hitIns.addEventListener('click', () => selectPart('insulator'));
    hitCond.addEventListener('click', () => selectPart('conductor'));
  </script>
</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 {
      width: 100%;
      height: 100%;
      background: #ffffff;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 16px;
      overflow-x: hidden;
    }
    .diagram-container {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 12px;
    }
    svg {
      width: 100%;
      height: auto;
      max-height: 320px;
      display: block;
    }
    .wire-glow {
      stroke: #38bdf8;
      stroke-width: 4;
      stroke-linecap: round;
      stroke-dasharray: 8 14;
      animation: flow 3s linear infinite;
    }
    @keyframes flow {
      from { stroke-dashoffset: 44; }
      to { stroke-dashoffset: 0; }
    }
    .bulb-glow {
      animation: pulse 3s ease-in-out infinite alternate;
      transform-origin: 250px 52px;
    }
    @keyframes pulse {
      0% { opacity: 0.75; transform: scale(0.97); }
      100% { opacity: 1; transform: scale(1.03); }
    }
    .badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: #ecfdf5;
      color: #065f46;
      border: 1.5px solid #10b981;
      padding: 7px 16px;
      border-radius: 9999px;
      font-size: 13px;
      font-weight: 700;
      letter-spacing: 0.2px;
      box-shadow: 0 1px 3px rgba(16, 185, 129, 0.15);
      text-align: center;
    }
    .badge-icon {
      font-size: 14px;
      line-height: 1;
    }
    .label {
      font-size: 12px;
      font-weight: 700;
      fill: #475569;
    }
  </style>
</head>
<body>

  <div class="diagram-container">
    <svg viewBox="0 0 460 265" aria-label="Testing circuit showing a steel paperclip acting as an electrical conductor to light a bulb">
      <defs>
        
        <radialGradient id="bulbGlowGrad" cx="50%" cy="50%" r="50%">
          <stop offset="0%" stop-color="#fef08a" stop-opacity="0.9" />
          <stop offset="50%" stop-color="#f59e0b" stop-opacity="0.4" />
          <stop offset="100%" stop-color="#f59e0b" stop-opacity="0" />
        </radialGradient>
        
        <linearGradient id="silverGrad" x1="0%" y1="0%" x2="100%" y2="100%">
          <stop offset="0%" stop-color="#f8fafc" />
          <stop offset="40%" stop-color="#cbd5e1" />
          <stop offset="70%" stop-color="#94a3b8" />
          <stop offset="100%" stop-color="#64748b" />
        </linearGradient>
      </defs>

      
      <g class="bulb-glow">
        <circle cx="250" cy="52" r="44" fill="url(#bulbGlowGrad)" />
        
        <line x1="250" y1="12" x2="250" y2="2" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" />
        <line x1="215" y1="23" x2="207" y2="15" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" />
        <line x1="285" y1="23" x2="293" y2="15" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" />
        <line x1="198" y1="52" x2="188" y2="52" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" />
        <line x1="302" y1="52" x2="312" y2="52" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" />
      </g>

      
      <path d="M 100 120 L 100 52 L 232 52 M 268 52 L 400 52 L 400 220 L 305 220 M 195 220 L 100 220 L 100 200" 
            fill="none" stroke="#334155" stroke-width="5" stroke-linecap="round" stroke-linejoin="round" />

      
      
      <path d="M 100 120 L 100 52 L 232 52 M 268 52 L 400 52 L 400 220 L 305 220 M 305 220 L 195 220 M 195 220 L 100 220 L 100 200" 
            fill="none" class="wire-glow" stroke-linejoin="round" />

      
      <circle cx="195" cy="220" r="6" fill="#0284c7" stroke="#0f172a" stroke-width="2" />
      <circle cx="305" cy="220" r="6" fill="#0284c7" stroke="#0f172a" stroke-width="2" />

      
      <g>
        <path d="M 190 225 L 300 225 A 7 7 0 0 0 300 211 L 205 211 A 5 5 0 0 0 205 221 L 285 221" 
              fill="none" stroke="url(#silverGrad)" stroke-width="4.5" stroke-linecap="round" stroke-linejoin="round" />
        <text x="250" y="248" class="label" text-anchor="middle">Steel Paperclip</text>
      </g>

      
      <g transform="translate(78, 120)">
        
        <text x="-12" y="44" class="label" text-anchor="end">Battery</text>
        
        <rect x="17" y="-6" width="10" height="6" rx="2" fill="#94a3b8" />
        
        <rect x="0" y="0" width="44" height="80" rx="6" fill="#3b82f6" stroke="#1d4ed8" stroke-width="2" />
        
        <rect x="0" y="0" width="44" height="24" rx="6" fill="#2563eb" />
        <text x="22" y="17" fill="#ffffff" font-size="16" font-weight="900" text-anchor="middle">+</text>
        
        <text x="22" y="70" fill="#ffffff" font-size="18" font-weight="900" text-anchor="middle">−</text>
        
        <text x="22" y="44" fill="#ffffff" font-size="11" font-weight="700" text-anchor="middle">1.5V</text>
      </g>

      
      <g transform="translate(250, 52)">
        
        <path d="M -14 0 C -22 -10 -20 -28 0 -28 C 20 -28 22 -10 14 0 Z" 
              fill="#fbbf24" stroke="#f59e0b" stroke-width="2" />
        
        <path d="M -5 0 L -3 -14 L 0 -10 L 3 -14 L 5 0" 
              fill="none" stroke="#d97706" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" />
        
        <rect x="-8" y="0" width="16" height="8" rx="1" fill="#94a3b8" stroke="#64748b" stroke-width="1.5" />
        <rect x="-6" y="8" width="12" height="4" rx="2" fill="#475569" />
        <text x="0" y="-34" class="label" text-anchor="middle">Light Bulb</text>
      </g>
    </svg>

    
    <div class="badge">
      <span class="badge-icon">✓</span>
      <span>Conductor: Electricity flows freely</span>
    </div>
  </div>

</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%;
      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: center;
      padding: 8px;
      overflow: hidden;
    }
    .diagram-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      width: 100%;
      max-width: 640px;
      height: 100%;
    }
    .panel {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      display: flex;
      flex-direction: column;
      position: relative;
      overflow: hidden;
    }
    .panel-header {
      padding: 8px 12px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      border-bottom: 1px solid #edf2f7;
      background: #ffffff;
    }
    .panel-title {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
    }
    .status-tag {
      font-size: 12px;
      font-weight: 700;
      padding: 2px 8px;
      border-radius: 999px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }
    .tag-blocked {
      background: #fee2e2;
      color: #b91c1c;
    }
    .tag-absorbed {
      background: #dcfce7;
      color: #15803d;
    }
    .scene {
      flex: 1;
      position: relative;
      width: 100%;
      height: 100%;
      min-height: 200px;
    }
    svg {
      width: 100%;
      height: 100%;
      display: block;
    }
    
    /* Subtle pulsing & movement animations */
    @keyframes tryPass {
      0%, 100% { transform: translate(32px, 95px); }
      45% { transform: translate(62px, 95px); }
      55% { transform: translate(58px, 95px); }
      70% { transform: translate(32px, 95px); }
    }
    @keyframes xPop {
      0%, 35%, 100% { opacity: 0; transform: scale(0.6); }
      50%, 80% { opacity: 1; transform: scale(1); }
      90% { opacity: 0; }
    }
    @keyframes flowNutrient1 {
      0% { transform: translate(25px, 90px); opacity: 0; }
      15% { opacity: 1; }
      50% { transform: translate(95px, 115px); }
      85% { opacity: 1; }
      100% { transform: translate(175px, 115px); opacity: 0; }
    }
    @keyframes flowNutrient2 {
      0% { transform: translate(20px, 125px); opacity: 0; }
      15% { opacity: 1; }
      50% { transform: translate(95px, 120px); }
      85% { opacity: 1; }
      100% { transform: translate(175px, 120px); opacity: 0; }
    }
    @keyframes flowNutrient3 {
      0% { transform: translate(35px, 150px); opacity: 0; }
      15% { opacity: 1; }
      50% { transform: translate(95px, 125px); }
      85% { opacity: 1; }
      100% { transform: translate(175px, 125px); opacity: 0; }
    }
    @keyframes checkPop {
      0%, 100% { transform: scale(1); }
      50% { transform: scale(1.1); }
    }

    .anim-chunk {
      animation: tryPass 3.2s ease-in-out infinite;
      transform-origin: center;
    }
    .anim-x {
      animation: xPop 3.2s ease-in-out infinite;
      transform-origin: 90px 120px;
    }
    .anim-n1 {
      animation: flowNutrient1 3.2s ease-in-out infinite;
    }
    .anim-n2 {
      animation: flowNutrient2 3.2s ease-in-out infinite 0.9s;
    }
    .anim-n3 {
      animation: flowNutrient3 3.2s ease-in-out infinite 1.8s;
    }
    .anim-check {
      animation: checkPop 3.2s ease-in-out infinite;
      transform-origin: 155px 40px;
    }

    .layer-label {
      font-size: 11px;
      font-weight: 600;
      fill: #64748b;
      letter-spacing: 0.5px;
      text-transform: uppercase;
    }
  </style>
</head>
<body>

  <div class="diagram-grid">
    
    <div class="panel">
      <div class="panel-header">
        <span class="panel-title">Large Food</span>
        <span class="status-tag tag-blocked">✕ Blocked</span>
      </div>
      <div class="scene">
        <svg viewBox="0 0 200 240" preserveAspectRatio="xMidYMid meet">
          
          <rect x="115" y="10" width="80" height="220" rx="8" fill="#fee2e2" opacity="0.6"/>
          
          
          <text x="25" y="28" class="layer-label">Gut</text>
          <text x="130" y="28" class="layer-label" fill="#dc2626">Blood</text>

          
          <rect x="86" y="40" width="16" height="55" rx="4" fill="#94a3b8"/>
          
          
          <rect x="86" y="145" width="16" height="85" rx="4" fill="#94a3b8"/>
          <text x="94" y="215" font-size="9" fill="#ffffff" font-weight="700" text-anchor="middle" transform="rotate(-90 94 215)">WALL</text>

          
          <line x1="82" y1="95" x2="82" y2="145" stroke="#cbd5e1" stroke-dasharray="2,2" stroke-width="1.5"/>

          
          <g class="anim-chunk">
            <rect x="0" y="0" width="50" height="50" rx="10" fill="#f59e0b" stroke="#d97706" stroke-width="2"/>
            
            <circle cx="15" cy="18" r="3" fill="#fbbf24"/>
            <circle cx="35" cy="20" r="3" fill="#fbbf24"/>
            <circle cx="25" cy="35" r="4" fill="#fbbf24"/>
          </g>

          
          <g class="anim-x">
            <circle cx="94" cy="120" r="16" fill="#ef4444"/>
            <path d="M 88 114 L 100 126 M 100 114 L 88 126" stroke="#ffffff" stroke-width="3.5" stroke-linecap="round"/>
          </g>
        </svg>
      </div>
    </div>

    
    <div class="panel">
      <div class="panel-header">
        <span class="panel-title">Tiny Nutrients</span>
        <span class="status-tag tag-absorbed">✓ Absorbed</span>
      </div>
      <div class="scene">
        <svg viewBox="0 0 200 240" preserveAspectRatio="xMidYMid meet">
          
          <rect x="115" y="10" width="80" height="220" rx="8" fill="#fee2e2" opacity="0.6"/>
          
          
          <text x="25" y="28" class="layer-label">Gut</text>
          <text x="130" y="28" class="layer-label" fill="#dc2626">Blood</text>

          
          <rect x="86" y="40" width="16" height="55" rx="4" fill="#94a3b8"/>
          
          <rect x="86" y="145" width="16" height="85" rx="4" fill="#94a3b8"/>
          <text x="94" y="215" font-size="9" fill="#ffffff" font-weight="700" text-anchor="middle" transform="rotate(-90 94 215)">WALL</text>

          
          <line x1="82" y1="95" x2="82" y2="145" stroke="#cbd5e1" stroke-dasharray="2,2" stroke-width="1.5"/>

          
          <g class="anim-n1">
            <circle cx="0" cy="0" r="6" fill="#10b981" stroke="#059669" stroke-width="1.5"/>
          </g>
          <g class="anim-n2">
            <circle cx="0" cy="0" r="6" fill="#10b981" stroke="#059669" stroke-width="1.5"/>
          </g>
          <g class="anim-n3">
            <circle cx="0" cy="0" r="6" fill="#10b981" stroke="#059669" stroke-width="1.5"/>
          </g>

          
          <g class="anim-check">
            <circle cx="155" cy="40" r="14" fill="#22c55e"/>
            <path d="M 149 40 L 153 44 L 161 36" stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round" fill="none"/>
          </g>
        </svg>
      </div>
    </div>
  </div>

</body>
</html>

Introduction to the Digestive System

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

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

    .process-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin-bottom: 16px;
      width: 100%;
    }

    @media (max-width: 520px) {
      .process-grid {
        grid-template-columns: 1fr;
        gap: 10px;
        margin-bottom: 12px;
      }
    }

    .step-card {
      background: #ffffff;
      border: 1.5px solid #e6e6e6;
      border-radius: 12px;
      padding: 12px 10px;
      text-align: center;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 142px;
      cursor: pointer;
      user-select: none;
      transition: border-color 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
      position: relative;
    }

    @media (max-width: 520px) {
      .step-card {
        min-height: auto;
        padding: 10px 12px;
        flex-direction: row;
        text-align: left;
        gap: 10px;
      }
    }

    .step-card:hover {
      border-color: #93c5fd;
      background-color: #fafcfe;
    }

    .step-card.active {
      border-color: #22b7ff;
      background-color: #f0f9ff;
      box-shadow: 0 4px 14px rgba(34, 183, 255, 0.28);
    }

    .step-header {
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    @media (max-width: 520px) {
      .step-header {
        align-items: flex-start;
        min-width: 90px;
      }
    }

    .step-number {
      font-size: 11px;
      font-weight: 800;
      text-transform: uppercase;
      letter-spacing: 0.6px;
      color: #475569;
      margin-bottom: 2px;
      transition: color 0.2s ease;
    }

    .step-card.active .step-number {
      color: #0284c7;
    }

    .step-title {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
    }

    .visual-stage {
      height: 48px;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      position: relative;
      margin: 4px 0;
    }

    @media (max-width: 520px) {
      .visual-stage {
        height: auto;
        width: auto;
        margin: 0;
        flex: 1;
      }
    }

    .icon-main {
      font-size: 24px;
      line-height: 1;
      display: inline-block;
    }

    .arrow {
      font-size: 13px;
      color: #64748b;
      font-weight: 800;
    }

    .sparkle {
      font-size: 18px;
      color: #0284c7;
      font-weight: bold;
    }

    .step-desc {
      font-size: 12.5px;
      font-weight: 600;
      color: #334155;
      line-height: 1.25;
    }

    @media (max-width: 520px) {
      .step-desc {
        min-width: 85px;
        text-align: right;
        font-size: 12px;
      }
    }

    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
    }

    .btn {
      background: #ffffff;
      border: 1.5px solid #d1d5db;
      border-radius: 8px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      user-select: none;
      transition: background 0.15s, border-color 0.15s, color 0.15s;
      min-width: 38px;
      height: 34px;
    }

    .btn:hover {
      background: #f8fafc;
      border-color: #94a3b8;
    }

    .btn:active {
      background: #e2e8f0;
    }

    .dots {
      display: flex;
      gap: 8px;
      align-items: center;
      padding: 0 4px;
    }

    .dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #94a3b8;
      cursor: pointer;
      transition: background-color 0.25s ease, outline 0.25s ease;
    }

    .dot:hover {
      background: #64748b;
    }

    .dot.active {
      background: #0284c7;
      outline: 2px solid #bae6fd;
    }
  </style>
</head>
<body>

  <div class="process-grid">
    
    <div class="step-card step active" id="card-0">
      <div class="step-header">
        <div class="step-number">Step 1</div>
        <div class="step-title">1. Crunch</div>
      </div>
      <div class="visual-stage">
        <span class="icon-main">🍎</span>
        <span class="arrow">➔</span>
        <span class="icon-main">🦷</span>
        <span class="arrow">➔</span>
        <span style="font-size:15px; letter-spacing: -2px;">🍎🍎</span>
      </div>
      <div class="step-desc">Chew to pieces</div>
    </div>

    
    <div class="step-card step" id="card-1">
      <div class="step-header">
        <div class="step-number">Step 2</div>
        <div class="step-title">2. Dissolve</div>
      </div>
      <div class="visual-stage">
        <span class="icon-main">🧪</span>
        <span class="arrow">➔</span>
        <span class="icon-main">💧</span>
        <span class="arrow">➔</span>
        <span class="sparkle">✨</span>
      </div>
      <div class="step-desc">Break to liquid</div>
    </div>

    
    <div class="step-card step" id="card-2">
      <div class="step-header">
        <div class="step-number">Step 3</div>
        <div class="step-title">3. Fuel Up</div>
      </div>
      <div class="visual-stage">
        <span class="sparkle">✨</span>
        <span class="arrow">➔</span>
        <span class="icon-main">⚡</span>
        <span class="arrow">➔</span>
        <span class="icon-main">💪</span>
      </div>
      <div class="step-desc">Absorb for energy</div>
    </div>
  </div>

  <div class="controls">
    <button class="btn" id="prevBtn" aria-label="Previous step">◀</button>
    <button class="btn" id="playBtn" aria-label="Play or pause playback"><span id="playIcon">⏸</span></button>
    <button class="btn" id="nextBtn" aria-label="Next step">▶</button>
    <div class="dots">
      <span class="dot active" data-step="0" aria-label="Step 1"></span>
      <span class="dot" data-step="1" aria-label="Step 2"></span>
      <span class="dot" data-step="2" aria-label="Step 3"></span>
    </div>
  </div>

  <script>
    class StepPlayer {
      constructor(selector, options = {}) {
        this.elements = Array.from(document.querySelectorAll(selector));
        this.currentIndex = 0;
        this.interval = options.interval || 3200;
        this.onChange = options.onChange || (() => {});
        this.timer = null;
        this.playing = false;
        this.update();
      }

      update() {
        this.elements.forEach((el, idx) => {
          el.classList.toggle('active', idx === this.currentIndex);
        });
        this.onChange(this.currentIndex);
      }

      goTo(index) {
        if (index >= 0 && index < this.elements.length) {
          this.currentIndex = index;
          this.update();
        }
      }

      next() {
        this.currentIndex = (this.currentIndex + 1) % this.elements.length;
        this.update();
      }

      prev() {
        this.currentIndex = (this.currentIndex - 1 + this.elements.length) % this.elements.length;
        this.update();
      }

      start() {
        if (this.playing) return;
        this.playing = true;
        this.timer = setInterval(() => {
          this.next();
        }, this.interval);
      }

      pause() {
        this.playing = false;
        if (this.timer) {
          clearInterval(this.timer);
          this.timer = null;
        }
      }

      toggle() {
        if (this.playing) {
          this.pause();
        } else {
          this.start();
        }
      }
    }

    function onTap(element, callback) {
      if (!element) return;
      element.addEventListener('click', callback);
    }

    const dots = document.querySelectorAll('.dot');
    const cards = document.querySelectorAll('.step-card');
    const playIcon = document.getElementById('playIcon');

    function updateView(index) {
      dots.forEach((dot, i) => {
        dot.classList.toggle('active', i === index);
      });
    }

    const player = new StepPlayer('.step', {
      interval: 3200,
      onChange: (index) => {
        updateView(index);
      }
    });

    player.start();

    // Wire interactive triggers
    cards.forEach((card, idx) => {
      onTap(card, () => {
        player.pause();
        player.goTo(idx);
        playIcon.textContent = '▶';
      });
    });

    dots.forEach((dot, idx) => {
      onTap(dot, () => {
        player.pause();
        player.goTo(idx);
        playIcon.textContent = '▶';
      });
    });

    onTap(document.getElementById('prevBtn'), () => {
      player.pause();
      player.prev();
      playIcon.textContent = '▶';
    });

    onTap(document.getElementById('nextBtn'), () => {
      player.pause();
      player.next();
      playIcon.textContent = '▶';
    });

    onTap(document.getElementById('playBtn'), () => {
      player.toggle();
      playIcon.textContent = player.playing ? '⏸' : '▶';
    });
  </script>
</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 {
      width: 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: center;
      padding: 10px;
      user-select: none;
    }

    .stepper-nav {
      display: flex;
      gap: 6px;
      margin-bottom: 12px;
      width: 100%;
      max-width: 340px;
      justify-content: center;
    }

    .step-btn {
      flex: 1;
      padding: 6px 4px;
      font-size: 12px;
      font-weight: 600;
      border: 1px solid #e6e6e6;
      border-radius: 8px;
      background: #ffffff;
      color: #6b7280;
      cursor: pointer;
      text-align: center;
      transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    }

    .step-btn.active {
      background: #22b7ff;
      color: #ffffff;
      border-color: #22b7ff;
      box-shadow: 0 2px 6px rgba(34, 183, 255, 0.3);
    }

    .diagram-svg {
      width: 100%;
      max-width: 340px;
      height: auto;
      display: block;
      overflow: visible;
    }

    /* Animation effects - smooth, stable keyframes */
    @keyframes gearSpin {
      from { transform: rotate(0deg); }
      to { transform: rotate(360deg); }
    }
    @keyframes gearSpinRev {
      from { transform: rotate(0deg); }
      to { transform: rotate(-360deg); }
    }
    @keyframes pulseEnergy {
      0%, 100% { transform: scale(1); filter: drop-shadow(0 0 2px rgba(40, 167, 69, 0.3)); }
      50% { transform: scale(1.05); filter: drop-shadow(0 0 6px rgba(40, 167, 69, 0.6)); }
    }
    @keyframes floatNutrient {
      0% { transform: translateX(0px); opacity: 0.1; }
      20% { opacity: 0.95; }
      80% { opacity: 0.95; }
      100% { transform: translateX(64px); opacity: 0.1; }
    }

    .gear-1 { transform-origin: 166px 82px; animation: gearSpin 6s linear infinite; }
    .gear-2 { transform-origin: 185px 98px; animation: gearSpinRev 6s linear infinite; }
    .runner-node { transform-origin: 295px 115px; }
    .runner-active { animation: pulseEnergy 2s ease-in-out infinite; }

    .dot-flow {
      animation: floatNutrient 2.6s cubic-bezier(0.4, 0, 0.2, 1) infinite;
    }
    .dot-flow-d1 { animation-delay: 0.85s; }
    .dot-flow-d2 { animation-delay: 1.7s; }

    .stage-group {
      transition: opacity 0.4s ease, filter 0.4s ease;
    }
    .dimmed {
      opacity: 0.35;
      filter: grayscale(40%);
    }
  </style>
</head>
<body>

  <div class="stepper-nav" role="tablist">
    <button class="step-btn active" id="btn-0" type="button">1. Food</button>
    <button class="step-btn" id="btn-1" type="button">2. Digestion</button>
    <button class="step-btn" id="btn-2" type="button">3. Energy</button>
  </div>

  <svg class="diagram-svg" viewBox="0 0 350 200" aria-label="Digestion process diagram">
    <defs>
      
      <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 8 5 L 0 8.5 z" fill="#22b7ff"/>
      </marker>
      
      <filter id="glow" x="-30%" y="-30%" width="160%" height="160%">
        <feGaussianBlur stdDeviation="1" result="blur" />
        <feComposite in="SourceGraphic" in2="blur" operator="over" />
      </filter>
    </defs>

    
    <g id="stage-0" class="stage-group">
      <rect x="8" y="16" width="95" height="152" rx="10" fill="#ffffff" stroke="#e6e6e6" stroke-width="1.5"/>
      <text x="55" y="36" font-size="13" font-weight="700" fill="#1e2945" text-anchor="middle">Food</text>
      <text x="55" y="52" font-size="11" font-weight="600" fill="#dc2626" text-anchor="middle">(Too Big)</text>
      
      
      <text x="55" y="104" font-size="42" text-anchor="middle" dominant-baseline="central">🍎</text>
      
      <rect x="16" y="136" width="79" height="22" rx="6" fill="#fee2e2" stroke="#fca5a5" stroke-width="1"/>
      <text x="55" y="151" font-size="10" font-weight="600" fill="#b91c1c" text-anchor="middle">Cannot Absorb</text>
    </g>

    
    <g id="stage-1" class="stage-group">
      
      <line x1="107" y1="92" x2="137" y2="92" stroke="#22b7ff" stroke-width="2.5" marker-end="url(#arrow)"/>
      
      <rect x="142" y="16" width="90" height="152" rx="10" fill="#ffffff" stroke="#e6e6e6" stroke-width="1.5"/>
      <text x="187" y="36" font-size="13" font-weight="700" fill="#1e2945" text-anchor="middle">Digestion</text>
      <text x="187" y="52" font-size="11" font-weight="600" fill="#22b7ff" text-anchor="middle">Breakdown</text>

      
      <g class="gear-1">
        <text x="166" y="82" font-size="22" text-anchor="middle" dominant-baseline="central">⚙️</text>
      </g>
      <g class="gear-2">
        <text x="185" y="98" font-size="18" text-anchor="middle" dominant-baseline="central">⚙️</text>
      </g>

      
      <text x="187" y="128" font-size="16" text-anchor="middle">✨</text>
      <text x="187" y="151" font-size="10" font-weight="600" fill="#6b7280" text-anchor="middle">Crushes Food</text>
    </g>

    
    <g id="stage-2" class="stage-group">
      
      <line x1="236" y1="92" x2="249" y2="92" stroke="#22b7ff" stroke-width="2.5" marker-end="url(#arrow)"/>

      <rect x="254" y="16" width="88" height="152" rx="10" fill="#ffffff" stroke="#e6e6e6" stroke-width="1.5"/>
      <text x="298" y="34" font-size="12" font-weight="700" fill="#1e2945" text-anchor="middle">Nutrients</text>
      <text x="298" y="47" font-size="10" font-weight="600" fill="#28a745" text-anchor="middle">(Right Size)</text>

      
      <text x="298" y="62" font-size="9" font-weight="700" fill="#dc2626" text-anchor="middle" letter-spacing="0.2">BLOODSTREAM</text>

      
      <rect x="259" y="67" width="78" height="20" rx="10" fill="#ffe4e6" stroke="#ef4444" stroke-width="1.2"/>

      
      <g>
        <circle class="dot-flow" cx="264" cy="77" r="3.5" fill="#f59e0b" filter="url(#glow)"/>
        <circle class="dot-flow dot-flow-d1" cx="264" cy="77" r="3.5" fill="#f59e0b" filter="url(#glow)"/>
        <circle class="dot-flow dot-flow-d2" cx="264" cy="77" r="3.5" fill="#f59e0b" filter="url(#glow)"/>
      </g>

      
      <g id="runner" class="runner-node">
        <text x="290" y="122" font-size="25" text-anchor="middle" dominant-baseline="central">🏃</text>
        <text x="314" y="112" font-size="15" text-anchor="middle" dominant-baseline="central">⚡</text>
      </g>
      
      <rect x="263" y="136" width="70" height="22" rx="6" fill="#dcfce7" stroke="#86efac" stroke-width="1"/>
      <text x="298" y="151" font-size="11" font-weight="700" fill="#166534" text-anchor="middle">Energy!</text>
    </g>

    
    <text x="175" y="188" font-size="12" font-weight="600" fill="#6b7280" text-anchor="middle">
      Digestion turns big food into tiny fuel!
    </text>
  </svg>

  <script>
    const stages = [
      document.getElementById('stage-0'),
      document.getElementById('stage-1'),
      document.getElementById('stage-2')
    ];
    const buttons = [
      document.getElementById('btn-0'),
      document.getElementById('btn-1'),
      document.getElementById('btn-2')
    ];
    const runner = document.getElementById('runner');

    let currentStep = 0;
    let autoInterval = null;

    function showStep(idx) {
      currentStep = idx;
      buttons.forEach((btn, i) => {
        if (btn) btn.classList.toggle('active', i === idx);
      });

      stages.forEach((stage, i) => {
        if (stage) {
          if (i === idx) {
            stage.classList.remove('dimmed');
          } else {
            stage.classList.add('dimmed');
          }
        }
      });

      if (runner) {
        if (idx === 2) {
          runner.classList.add('runner-active');
        } else {
          runner.classList.remove('runner-active');
        }
      }
    }

    buttons.forEach((btn, i) => {
      if (btn) {
        btn.addEventListener('click', () => {
          clearInterval(autoInterval);
          showStep(i);
          startCycle();
        });
      }
    });

    function startCycle() {
      autoInterval = setInterval(() => {
        currentStep = (currentStep + 1) % 3;
        showStep(currentStep);
      }, 3500);
    }

    showStep(0);
    startCycle();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Apparent vs Real Motion of the Sun</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #0f172a;
      background: transparent;
      padding: 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: 100%;
    }

    .widget-container {
      width: 100%;
      max-width: 660px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .panels {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
      width: 100%;
    }

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

    .panel {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 10px;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      position: relative;
    }

    .panel-header {
      padding: 6px 10px;
      background: #f8fafc;
      border-bottom: 1px solid #e2e8f0;
      font-size: 13px;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: space-between;
      color: #0f172a;
      z-index: 10;
    }

    .badge {
      font-size: 10px;
      font-weight: 700;
      padding: 2px 6px;
      border-radius: 4px;
      text-transform: uppercase;
      letter-spacing: 0.3px;
    }

    .badge-apparent {
      background: #fef3c7;
      color: #92400e;
      border: 1px solid #fde68a;
    }

    .badge-actual {
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #bae6fd;
    }

    .scene {
      position: relative;
      width: 100%;
      height: 165px;
      overflow: hidden;
      contain: paint;
    }

    /* === LEFT PANEL: WHAT WE SEE === */
    .sky-scene {
      background: #7dd3fc;
      animation: skyCycle 6s linear infinite;
    }

    .stars-layer {
      position: absolute;
      inset: 0;
      background-image: 
        radial-gradient(1.5px 1.5px at 15% 20%, #ffffff 100%, transparent),
        radial-gradient(1.5px 1.5px at 35% 45%, #ffffff 100%, transparent),
        radial-gradient(1.5px 1.5px at 60% 25%, #ffffff 100%, transparent),
        radial-gradient(1.5px 1.5px at 80% 35%, #ffffff 100%, transparent),
        radial-gradient(2px 2px at 88% 18%, #ffffff 100%, transparent),
        radial-gradient(1.5px 1.5px at 25% 65%, #ffffff 100%, transparent),
        radial-gradient(1.5px 1.5px at 70% 60%, #ffffff 100%, transparent);
      opacity: 0;
      animation: starsFade 6s linear infinite;
      pointer-events: none;
    }

    .arc-visual {
      position: absolute;
      bottom: 28px;
      left: 50%;
      transform: translateX(-50%);
      width: 210px;
      height: 105px;
      border: 2px dashed rgba(245, 158, 11, 0.6);
      border-bottom: none;
      border-top-left-radius: 110px;
      border-top-right-radius: 110px;
      pointer-events: none;
    }

    .sun-orbit-arm {
      position: absolute;
      bottom: 28px;
      left: 50%;
      width: 2px;
      height: 105px;
      transform-origin: bottom center;
      animation: sunTravel 6s linear infinite;
      pointer-events: none;
    }

    .sun-body {
      position: absolute;
      top: -16px;
      left: -16px;
      width: 32px;
      height: 32px;
      background: #f59e0b;
      border: 2px solid #d97706;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 16px;
      box-shadow: 0 0 14px #fbbf24;
      pointer-events: auto;
    }

    .moon-orbit-arm {
      position: absolute;
      bottom: 28px;
      left: 50%;
      width: 2px;
      height: 105px;
      transform-origin: bottom center;
      animation: moonTravel 6s linear infinite;
      pointer-events: none;
    }

    .moon-body {
      position: absolute;
      top: -12px;
      left: -12px;
      width: 24px;
      height: 24px;
      background: #f8fafc;
      border: 2px solid #cbd5e1;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 13px;
      box-shadow: 0 0 10px #f8fafc;
      pointer-events: auto;
    }

    .ground-layer {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 32px;
      background: #22c55e;
      border-top: 3px solid #16a34a;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 8px;
      z-index: 5;
    }

    .dir-badge {
      font-size: 10px;
      font-weight: 800;
      color: #064e3b;
      background: rgba(255, 255, 255, 0.9);
      padding: 2px 6px;
      border-radius: 4px;
      box-shadow: 0 1px 2px rgba(0,0,0,0.1);
      border: 1px solid rgba(22, 163, 74, 0.4);
    }

    .observer-icon {
      position: absolute;
      bottom: 26px;
      left: 50%;
      transform: translateX(-50%);
      font-size: 22px;
      z-index: 6;
      filter: drop-shadow(0 2px 2px rgba(0,0,0,0.3));
    }

    /* === RIGHT PANEL: WHAT ACTUALLY HAPPENS === */
    .space-scene {
      background: #090d16;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .space-stars {
      position: absolute;
      inset: 0;
      background-image: 
        radial-gradient(1px 1px at 10% 15%, #94a3b8 100%, transparent),
        radial-gradient(1.5px 1.5px at 30% 75%, #ffffff 100%, transparent),
        radial-gradient(1px 1px at 50% 20%, #94a3b8 100%, transparent),
        radial-gradient(1px 1px at 70% 85%, #cbd5e1 100%, transparent),
        radial-gradient(1.5px 1.5px at 85% 15%, #ffffff 100%, transparent);
      pointer-events: none;
    }

    .earth-system {
      position: absolute;
      left: 36px;
      top: 50%;
      transform: translateY(-50%);
      width: 90px;
      height: 90px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .earth-body {
      position: absolute;
      width: 76px;
      height: 76px;
      border-radius: 50%;
      background: linear-gradient(to right, #1e293b 50%, #38bdf8 50%);
      box-shadow: 0 0 0 1.5px #64748b, 0 0 16px rgba(56, 189, 248, 0.2);
      overflow: hidden;
    }

    .pole-marker {
      position: absolute;
      width: 22px;
      height: 22px;
      border-radius: 50%;
      background: #f1f5f9;
      border: 1.5px solid #475569;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 8px;
      font-weight: 800;
      color: #0f172a;
      z-index: 4;
      pointer-events: none;
    }

    .earth-rotor {
      position: absolute;
      inset: 0;
      border-radius: 50%;
      animation: earthSpin 6s linear infinite;
    }

    .person-pin {
      position: absolute;
      bottom: 2px;
      left: 50%;
      transform: translateX(-50%);
      width: 14px;
      height: 14px;
      background: #ef4444;
      border: 2px solid #ffffff;
      border-radius: 50%;
      box-shadow: 0 0 6px rgba(239, 68, 68, 0.9);
      z-index: 5;
    }

    .rot-indicator {
      position: absolute;
      inset: -10px;
      border: 1.5px dashed #38bdf8;
      border-radius: 50%;
      pointer-events: none;
    }

    .rot-arrow-lbl {
      position: absolute;
      top: -2px;
      left: 50%;
      transform: translateX(-50%);
      font-size: 10px;
      color: #38bdf8;
      font-weight: 800;
      line-height: 1;
    }

    .sun-light-beam {
      position: absolute;
      right: 48px;
      left: 110px;
      top: 25px;
      bottom: 25px;
      background: linear-gradient(to left, rgba(251, 191, 36, 0.28), rgba(251, 191, 36, 0.03));
      clip-path: polygon(100% 15%, 0% 0%, 0% 100%, 100% 85%);
      pointer-events: none;
    }

    .sun-stationary {
      position: absolute;
      right: 12px;
      top: 50%;
      transform: translateY(-50%);
      width: 44px;
      height: 44px;
      background: radial-gradient(circle, #fde047 30%, #f59e0b 90%);
      border-radius: 50%;
      box-shadow: 0 0 20px #f59e0b, 0 0 35px rgba(251, 191, 36, 0.5);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      font-size: 9px;
      font-weight: 800;
      color: #78350f;
      border: 2px solid #fbbf24;
      z-index: 5;
    }

    .caption-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 5px 10px;
      background: #f8fafc;
      border-top: 1px solid #e2e8f0;
      font-size: 11px;
      font-weight: 600;
      color: #334155;
      min-height: 28px;
    }

    .caption-highlight {
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    .dot-red {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #ef4444;
      display: inline-block;
    }

    .controls-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      padding-top: 2px;
    }

    .btn-toggle {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #1e293b;
      padding: 6px 14px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      outline: none;
      transition: background 0.15s, border-color 0.15s;
    }

    .btn-toggle:hover {
      background: #e2e8f0;
      border-color: #94a3b8;
    }

    .btn-toggle:focus-visible {
      outline: 2px solid #0284c7;
    }

    /* === ANIMATIONS (Synchronized 6s cycle) === */
    /* 0% = Dawn / Sunrise */
    /* 25% (1.5s) = Noon */
    /* 50% (3.0s) = Sunset / Dusk */
    /* 75% (4.5s) = Midnight */
    /* 100% (6.0s) = Dawn */

    @keyframes sunTravel {
      0% {
        transform: rotate(-90deg);
        opacity: 0;
      }
      3% {
        opacity: 1;
      }
      25% {
        transform: rotate(0deg);
        opacity: 1;
      }
      47% {
        opacity: 1;
      }
      50% {
        transform: rotate(90deg);
        opacity: 0;
      }
      100% {
        transform: rotate(90deg);
        opacity: 0;
      }
    }

    @keyframes moonTravel {
      0%, 48% {
        transform: rotate(-90deg);
        opacity: 0;
      }
      52% {
        opacity: 1;
      }
      75% {
        transform: rotate(0deg);
        opacity: 1;
      }
      97% {
        opacity: 1;
      }
      100% {
        transform: rotate(90deg);
        opacity: 0;
      }
    }

    @keyframes skyCycle {
      0% {
        background: #fdba74; /* Sunrise orange */
      }
      12% {
        background: #7dd3fc; /* Daytime sky blue */
      }
      38% {
        background: #38bdf8; /* Clear noon blue */
      }
      48% {
        background: #fb923c; /* Sunset orange */
      }
      55% {
        background: #0f172a; /* Night dark */
      }
      92% {
        background: #0f172a; /* Night dark */
      }
      100% {
        background: #fdba74; /* Sunrise */
      }
    }

    @keyframes starsFade {
      0%, 48% {
        opacity: 0;
      }
      55% {
        opacity: 0.9;
      }
      92% {
        opacity: 0.9;
      }
      100% {
        opacity: 0;
      }
    }

    /* Counter-clockwise rotation (looking down at North Pole) */
    /* Starting at bottom (Dawn), moves to right (Noon), top (Dusk), left (Midnight) */
    @keyframes earthSpin {
      0% {
        transform: rotate(0deg);
      }
      100% {
        transform: rotate(-360deg);
      }
    }

    .is-paused * {
      animation-play-state: paused !important;
    }
  </style>
</head>
<body>

  <div class="widget-container">
    <div class="panels" id="animationGroup">
      
      
      <div class="panel">
        <div class="panel-header">
          <span>What We See</span>
          <span class="badge badge-apparent">Apparent Motion</span>
        </div>
        <div class="scene sky-scene">
          <div class="stars-layer"></div>
          <div class="arc-visual"></div>
          
          
          <div class="sun-orbit-arm">
            <div class="sun-body" title="Sun rising in East, setting in West">☀️</div>
          </div>

          
          <div class="moon-orbit-arm">
            <div class="moon-body" title="Moon at night">🌙</div>
          </div>

          
          <div class="observer-icon" title="You on Earth">🧍</div>
          <div class="ground-layer">
            <span class="dir-badge">🌅 East (Sunrise)</span>
            <span class="dir-badge">West (Sunset) 🌇</span>
          </div>
        </div>
        <div class="caption-bar">
          <span>Sun moves East ➔ West</span>
          <span style="color: #64748b;">Earth feels still</span>
        </div>
      </div>

      
      <div class="panel">
        <div class="panel-header">
          <span>What Actually Happens</span>
          <span class="badge badge-actual">Space View</span>
        </div>
        <div class="scene space-scene">
          <div class="space-stars"></div>
          
          
          <div class="earth-system">
            <div class="rot-indicator">
              <div class="rot-arrow-lbl">◀</div>
            </div>
            <div class="earth-body"></div>
            <div class="pole-marker" title="North Pole">NP</div>
            <div class="earth-rotor">
              <div class="person-pin" title="You on Earth"></div>
            </div>
          </div>

          
          <div class="sun-light-beam"></div>
          <div class="sun-stationary">
            <span>SUN</span>
          </div>
        </div>
        <div class="caption-bar">
          <span class="caption-highlight"><span class="dot-red"></span> Red Pin = You</span>
          <span>Earth rotates (CCW)</span>
        </div>
      </div>

    </div>

    
    <div class="controls-row">
      <button class="btn-toggle" id="btnToggle" onclick="togglePlayState()">
        <span id="btnIcon">⏸</span>
        <span id="btnText">Pause Animation</span>
      </button>
    </div>
  </div>

  <script>
    let isRunning = true;
    const group = document.getElementById('animationGroup');
    const icon = document.getElementById('btnIcon');
    const text = document.getElementById('btnText');

    function togglePlayState() {
      isRunning = !isRunning;
      if (isRunning) {
        group.classList.remove('is-paused');
        icon.textContent = '⏸';
        text.textContent = 'Pause Animation';
      } else {
        group.classList.add('is-paused');
        icon.textContent = '▶';
        text.textContent = 'Play Animation';
      }
    }
  </script>
</body>
</html>

How Earth's Rotation Creates Day and Night

<!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;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 8px;
    }

    .svg-wrap {
      width: 100%;
      max-width: 420px;
      aspect-ratio: 1 / 1;
      position: relative;
    }

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

    /* Controls */
    .controls {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
      justify-content: center;
      align-items: center;
      width: 100%;
      max-width: 420px;
      margin-top: 6px;
    }

    .btn-step {
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      color: #475569;
      font-size: 13px;
      font-weight: 600;
      padding: 6px 10px;
      border-radius: 20px;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, border-color 0.2s, color 0.2s, box-shadow 0.2s;
    }

    .btn-step:hover {
      border-color: #94a3b8;
    }

    .btn-step.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.35);
    }

    .btn-play {
      background: #f1f5f9;
      border: 1.5px solid #cbd5e1;
      color: #334155;
      font-size: 13px;
      font-weight: bold;
      padding: 6px 12px;
      border-radius: 20px;
      cursor: pointer;
    }

    /* SVG Interactive nodes */
    .time-node {
      cursor: pointer;
    }

    .node-bg {
      fill: #ffffff;
      stroke: #cbd5e1;
      stroke-width: 1.5;
      transition: fill 0.25s, stroke 0.25s, stroke-width 0.25s;
    }

    .time-node.active .node-bg {
      fill: #0284c7;
      stroke: #38bdf8;
      stroke-width: 2.5;
    }

    .node-text-title {
      font-size: 12px;
      font-weight: 700;
      fill: #1e293b;
      text-anchor: middle;
      transition: fill 0.25s;
    }

    .node-text-sub {
      font-size: 10px;
      font-weight: 600;
      fill: #64748b;
      text-anchor: middle;
      transition: fill 0.25s;
    }

    .time-node.active .node-text-title {
      fill: #ffffff;
    }

    .time-node.active .node-text-sub {
      fill: #e0f2fe;
    }

    .observer-pin {
      transition: transform 0.45s cubic-bezier(0.34, 1.56, 0.64, 1);
    }
  </style>
</head>
<body>

  <div class="svg-wrap">
    <svg viewBox="0 0 420 400" aria-label="Earth 24-hour rotation diagram">
      <defs>
        
        <linearGradient id="sunbeam" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#fef08a" stop-opacity="0.85" />
          <stop offset="100%" stop-color="#fef08a" stop-opacity="0.05" />
        </linearGradient>

        
        <marker id="arrow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 1 2 L 7 5 L 1 8 z" fill="#0284c7" />
        </marker>
        <marker id="arrow-sm" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="5" markerHeight="5" orient="auto-start-reverse">
          <path d="M 1 2 L 7 5 L 1 8 z" fill="#0284c7" />
        </marker>
      </defs>

      
      <polygon points="10,60 210,105 210,295 10,340" fill="url(#sunbeam)" />
      
      
      <g transform="translate(16, 200)">
        <circle cx="0" cy="0" r="16" fill="#eab308" stroke="#ca8a04" stroke-width="2" />
        <path d="M 0 -22 L 0 -27 M 0 22 L 0 27 M -22 0 L -27 0 M 22 0 L 27 0 M -16 -16 L -20 -20 M 16 16 L 20 20 M -16 16 L -20 20 M 16 -16 L 20 -20" stroke="#ca8a04" stroke-width="2.5" stroke-linecap="round" />
        <text x="0" y="38" text-anchor="middle" font-size="11" font-weight="700" fill="#a16207">Sunlight</text>
      </g>

      
      
      <path d="M 225 115 A 85 85 0 0 0 225 285 Z" fill="#60a5fa" stroke="#0284c7" stroke-width="2" />
      
      <path d="M 180 145 Q 160 170 185 200 Q 165 240 195 260 A 85 85 0 0 1 180 145 Z" fill="#86efac" opacity="0.8" />
      
      
      <path d="M 225 115 A 85 85 0 0 1 225 285 Z" fill="#0f172a" stroke="#0284c7" stroke-width="2" />
      
      <circle cx="265" cy="155" r="1.5" fill="#ffffff" opacity="0.8" />
      <circle cx="285" cy="225" r="1.2" fill="#ffffff" opacity="0.7" />
      <circle cx="255" cy="250" r="1.5" fill="#ffffff" opacity="0.8" />

      
      <text x="175" y="204" font-size="12" font-weight="700" fill="#0369a1" opacity="0.65" text-anchor="middle">DAY</text>
      <text x="275" y="204" font-size="12" font-weight="700" fill="#94a3b8" opacity="0.65" text-anchor="middle">NIGHT</text>

      
      <circle cx="225" cy="200" r="4" fill="#0284c7" />
      <path d="M 225 184 A 16 16 0 1 0 241 200" fill="none" stroke="#0284c7" stroke-width="2" marker-end="url(#arrow-sm)" />
      <text x="225" y="176" font-size="9" font-weight="700" fill="#0369a1" text-anchor="middle">N. Pole</text>

      
      <path d="M 330 200 A 105 105 0 0 0 225 95" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="4 4" marker-end="url(#arrow)" />
      <path d="M 225 95 A 105 105 0 0 0 120 200" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="4 4" marker-end="url(#arrow)" />
      <path d="M 120 200 A 105 105 0 0 0 225 305" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="4 4" marker-end="url(#arrow)" />
      <path d="M 225 305 A 105 105 0 0 0 330 200" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="4 4" marker-end="url(#arrow)" />

      
      <g id="observerGroup" class="observer-pin" transform="translate(225, 115)">
        <circle cx="0" cy="0" r="11" fill="#f59e0b" stroke="#ffffff" stroke-width="2" />
        <text x="0" y="4" font-size="11" text-anchor="middle">📍</text>
      </g>

      
      <g class="time-node active" id="node-0" onclick="goToStep(0)" transform="translate(225, 52)">
        <rect class="node-bg" x="-48" y="-20" width="96" height="40" rx="20" />
        <text class="node-text-title" y="-2">Sunrise</text>
        <text class="node-text-sub" y="12">6:00 AM</text>
      </g>

      
      <g class="time-node" id="node-1" onclick="goToStep(1)" transform="translate(68, 200)">
        <rect class="node-bg" x="-44" y="-20" width="88" height="40" rx="20" />
        <text class="node-text-title" y="-2">Noon</text>
        <text class="node-text-sub" y="12">12:00 PM</text>
      </g>

      
      <g class="time-node" id="node-2" onclick="goToStep(2)" transform="translate(225, 348)">
        <rect class="node-bg" x="-48" y="-20" width="96" height="40" rx="20" />
        <text class="node-text-title" y="-2">Sunset</text>
        <text class="node-text-sub" y="12">6:00 PM</text>
      </g>

      
      <g class="time-node" id="node-3" onclick="goToStep(3)" transform="translate(365, 200)">
        <rect class="node-bg" x="-48" y="-20" width="96" height="40" rx="20" />
        <text class="node-text-title" y="-2">Midnight</text>
        <text class="node-text-sub" y="12">12:00 AM</text>
      </g>
    </svg>
  </div>

  
  <div class="controls">
    <button class="btn-step active" id="btn-0" onclick="goToStep(0)">🌅 Sunrise</button>
    <button class="btn-step" id="btn-1" onclick="goToStep(1)">☀️ Noon</button>
    <button class="btn-step" id="btn-2" onclick="goToStep(2)">🌇 Sunset</button>
    <button class="btn-step" id="btn-3" onclick="goToStep(3)">🌙 Midnight</button>
    <button class="btn-play" id="playBtn" onclick="togglePlay()">⏸</button>
  </div>

  <script>
    const positions = [
      { x: 225, y: 115 }, // Sunrise (Top)
      { x: 140, y: 200 }, // Noon (Left)
      { x: 225, y: 285 }, // Sunset (Bottom)
      { x: 310, y: 200 }  // Midnight (Right)
    ];

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

    function render() {
      // Update nodes and buttons
      for (let i = 0; i < 4; i++) {
        const node = document.getElementById(`node-${i}`);
        const btn = document.getElementById(`btn-${i}`);
        if (i === currentStep) {
          node.classList.add('active');
          btn.classList.add('active');
        } else {
          node.classList.remove('active');
          btn.classList.remove('active');
        }
      }

      // Move observer pin along Earth's surface
      const pin = document.getElementById('observerGroup');
      const pos = positions[currentStep];
      pin.setAttribute('transform', `translate(${pos.x}, ${pos.y})`);
    }

    function goToStep(step) {
      currentStep = step;
      render();
    }

    function nextStep() {
      currentStep = (currentStep + 1) % 4;
      render();
    }

    function togglePlay() {
      isPlaying = !isPlaying;
      document.getElementById('playBtn').textContent = isPlaying ? '⏸' : '▶';
      if (isPlaying) {
        startTimer();
      } else {
        clearInterval(timer);
      }
    }

    function startTimer() {
      clearInterval(timer);
      timer = setInterval(() => {
        nextStep();
      }, 3200);
    }

    // Initialize
    render();
    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 {
      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: 12px;
    }

    .main-stage {
      width: 100%;
      max-width: 540px;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    /* Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      margin: 8px 0;
    }

    .btn {
      appearance: none;
      border: 1px solid #d1d5db;
      background: #f8fafc;
      color: #1e2945;
      font-size: 14px;
      font-weight: 600;
      padding: 8px 16px;
      border-radius: 20px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background 0.2s, box-shadow 0.2s;
    }

    .btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.3);
    }

    /* Legend Box */
    .legend-box {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 8px 16px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 16px;
      font-size: 13px;
      font-weight: 500;
      color: #475569;
      max-width: 520px;
      width: 100%;
    }

    .legend-item {
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .legend-item strong {
      color: #0f172a;
    }

    .red-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #ef4444;
      display: inline-block;
    }

    /* Globe dynamic elements */
    #stickerGroup {
      transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="btn active" id="btnDay" onclick="setPhase(0)">☀️ Day (Facing Light)</button>
    <button class="btn" id="btnNight" onclick="setPhase(1)">🌙 Night (Facing Away)</button>
    <button class="btn" id="btnSpin" onclick="toggleSpin()">▶ Spin</button>
  </div>

  
  <div class="main-stage">
    <svg viewBox="0 0 520 250" aria-label="Flashlight illuminating a desktop globe to model day and night">
      <defs>
        
        <linearGradient id="beamGrad" x1="0%" y1="50%" x2="100%" y2="50%">
          <stop offset="0%" stop-color="#fbbf24" stop-opacity="0.9" />
          <stop offset="70%" stop-color="#fef08a" stop-opacity="0.4" />
          <stop offset="100%" stop-color="#fef08a" stop-opacity="0.05" />
        </linearGradient>

        
        <clipPath id="globeClip">
          <circle cx="390" cy="120" r="60" />
        </clipPath>

        
        <linearGradient id="shadowGrad" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="45%" stop-color="#0f172a" stop-opacity="0" />
          <stop offset="55%" stop-color="#0f172a" stop-opacity="0.75" />
        </linearGradient>
      </defs>

      
      <polygon points="120,110 390,60 390,180 120,130" fill="url(#beamGrad)" />

      
      <g transform="translate(10, 85)">
        
        <path d="M 40 25 L 85 25 L 85 45 L 40 45 Z" fill="#475569" rx="2" />
        <path d="M 85 20 L 105 15 L 105 55 L 85 50 Z" fill="#64748b" />
        <ellipse cx="105" cy="35" rx="4" ry="20" fill="#fde047" />
        
        <line x1="50" y1="28" x2="50" y2="42" stroke="#334155" stroke-width="2" />
        <line x1="60" y1="28" x2="60" y2="42" stroke="#334155" stroke-width="2" />
        <line x1="70" y1="28" x2="70" y2="42" stroke="#334155" stroke-width="2" />
        
        
        <path d="M 15 50 C 25 45, 45 42, 65 42 C 75 42, 75 52, 60 55 C 50 57, 30 58, 15 65 Z" fill="#fed7aa" />
        <circle cx="48" cy="38" r="6" fill="#fed7aa" />
        <circle cx="58" cy="38" r="6" fill="#fed7aa" />
        <circle cx="68" cy="38" r="6" fill="#fed7aa" />
      </g>

      
      <g stroke="#64748b" stroke-width="4" stroke-linecap="round" fill="none">
        
        <ellipse cx="390" cy="215" rx="36" ry="7" fill="#94a3b8" stroke="none" />
        <path d="M 390 190 L 390 215" stroke-width="6" />
        
        <path d="M 390 48 A 72 72 0 0 1 390 192" />
        
        <line x1="365" y1="52" x2="415" y2="188" stroke="#cbd5e1" stroke-width="3" />
      </g>

      
      <g clip-path="url(#globeClip)">
        
        <circle cx="390" cy="120" r="60" fill="#38bdf8" />

        
        
        <path d="M 355 88 Q 370 80 380 92 Q 388 105 375 118 Q 360 110 355 88 Z" fill="#4ade80" />
        
        <path d="M 378 125 Q 390 135 385 155 Q 375 160 372 140 Z" fill="#4ade80" />
        
        <path d="M 410 85 Q 430 80 440 100 Q 425 125 415 110 Z" fill="#4ade80" />
        <path d="M 418 120 Q 435 130 430 155 Q 415 150 415 130 Z" fill="#4ade80" />

        
        <rect x="330" y="60" width="120" height="120" fill="url(#shadowGrad)" />
      </g>

      
      <g transform="translate(390, 28)">
        <path d="M -30 6 Q 0 -6 30 6" fill="none" stroke="#0284c7" stroke-width="3" stroke-linecap="round" />
        <polygon points="32,9 26,0 35,3" fill="#0284c7" />
      </g>

      
      
      <g id="stickerGroup" transform="translate(368, 102)">
        
        <circle cx="0" cy="0" r="6.5" fill="#ef4444" stroke="#ffffff" stroke-width="2" />
        
        <g id="stickerLabel" transform="translate(0, -14)">
          <rect x="-18" y="-14" width="36" height="15" rx="4" fill="#0f172a" />
          <text x="0" y="-3" text-anchor="middle" fill="#ffffff" font-size="10" font-weight="700">YOU</text>
        </g>
      </g>
    </svg>
  </div>

  
  <div class="legend-box">
    <div class="legend-item">
      <span>🔦 <strong>Flashlight</strong> = Sun (Still)</span>
    </div>
    <div class="legend-item">
      <span>🌍 <strong>Globe</strong> = Earth (Spinning)</span>
    </div>
    <div class="legend-item">
      <span class="red-dot"></span>
      <span><strong>Sticker</strong> = You (Day & Night)</span>
    </div>
  </div>

  <script>
    let currentPhase = 0; // 0 = Day, 1 = Night
    let spinInterval = null;

    const sticker = document.getElementById('stickerGroup');
    const stickerLabel = document.getElementById('stickerLabel');
    const btnDay = document.getElementById('btnDay');
    const btnNight = document.getElementById('btnNight');
    const btnSpin = document.getElementById('btnSpin');

    function setPhase(phase) {
      currentPhase = phase;
      btnDay.classList.toggle('active', currentPhase === 0);
      btnNight.classList.toggle('active', currentPhase === 1);

      if (currentPhase === 0) {
        // DAY: Facing left towards flashlight (Lit side)
        sticker.style.transform = 'translate(368px, 102px)';
        sticker.style.opacity = '1';
      } else {
        // NIGHT: Facing right away from flashlight (Shadow side)
        sticker.style.transform = 'translate(418px, 106px)';
        sticker.style.opacity = '0.7';
      }
    }

    function toggleSpin() {
      if (spinInterval) {
        clearInterval(spinInterval);
        spinInterval = null;
        btnSpin.innerHTML = '▶ Spin';
        btnSpin.classList.remove('active');
      } else {
        btnSpin.innerHTML = '⏸ Pause';
        btnSpin.classList.add('active');
        spinInterval = setInterval(() => {
          setPhase(currentPhase === 0 ? 1 : 0);
        }, 1600);
      }
    }
  </script>
</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-color: #f8fafc;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      padding: 12px;
      user-select: none;
    }
    .diagram-wrap {
      width: 100%;
      max-width: 680px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 14px;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      width: 100%;
      flex-wrap: wrap;
    }
    .btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      padding: 8px 16px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.06);
      transition: background-color 0.2s, border-color 0.2s;
    }
    .btn:hover {
      background-color: #f1f5f9;
      border-color: #94a3b8;
    }
    .status-badge {
      background: #fef08a;
      color: #854d0e;
      padding: 8px 16px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 700;
      min-width: 140px;
      text-align: center;
      border: 1px solid #facc15;
      transition: background-color 0.3s, color 0.3s, border-color 0.3s;
    }
    .label {
      font-size: 13px;
      font-weight: 700;
      fill: #1e2945;
    }
    .label-muted {
      font-size: 11.5px;
      font-weight: 600;
      fill: #64748b;
    }
    .badge-text {
      font-size: 12px;
      font-weight: 800;
      letter-spacing: 0.6px;
    }
  </style>
</head>
<body>

<div class="diagram-wrap">
  <svg viewBox="0 0 720 400" aria-label="Earth rotation causing day and night diagram">
    <defs>
      
      <radialGradient id="sunGlow" cx="50%" cy="50%" r="50%">
        <stop offset="0%" stop-color="#ffffff" />
        <stop offset="30%" stop-color="#fffbeb" />
        <stop offset="60%" stop-color="#fde047" />
        <stop offset="85%" stop-color="#eab308" />
        <stop offset="100%" stop-color="#ca8a04" stop-opacity="0" />
      </radialGradient>

      
      <radialGradient id="earthDay" cx="35%" cy="45%" r="65%">
        <stop offset="0%" stop-color="#60a5fa" />
        <stop offset="70%" stop-color="#2563eb" />
        <stop offset="100%" stop-color="#1d4ed8" />
      </radialGradient>

      
      <linearGradient id="nightShadow" x1="0%" y1="0%" x2="100%" y2="0%">
        <stop offset="46%" stop-color="#020617" stop-opacity="0" />
        <stop offset="54%" stop-color="#020617" stop-opacity="0.82" />
        <stop offset="100%" stop-color="#020617" stop-opacity="0.95" />
      </linearGradient>

      
      <clipPath id="earthClip">
        <circle cx="480" cy="195" r="85" />
      </clipPath>

      
      <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="#0284c7" />
      </marker>
      <marker id="sunRay" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="5" markerHeight="5" orient="auto-start-reverse">
        <path d="M 0 2 L 8 5 L 0 8 z" fill="#eab308" />
      </marker>
    </defs>

    
    <g fill="#94a3b8" opacity="0.6">
      <circle cx="610" cy="50" r="1.5" />
      <circle cx="675" cy="90" r="1.2" />
      <circle cx="630" cy="140" r="1.5" />
      <circle cx="685" cy="220" r="1.2" />
      <circle cx="620" cy="300" r="1.5" />
      <circle cx="670" cy="350" r="1.2" />
    </g>

    
    <g id="sunGroup">
      
      <g stroke="#eab308" stroke-width="2.5" stroke-dasharray="6 4" opacity="0.85">
        <line x1="145" y1="125" x2="375" y2="125" marker-end="url(#sunRay)" />
        <line x1="155" y1="160" x2="385" y2="160" marker-end="url(#sunRay)" />
        <line x1="160" y1="195" x2="390" y2="195" marker-end="url(#sunRay)" />
        <line x1="155" y1="230" x2="385" y2="230" marker-end="url(#sunRay)" />
        <line x1="145" y1="265" x2="375" y2="265" marker-end="url(#sunRay)" />
      </g>

      
      <circle cx="80" cy="195" r="70" fill="url(#sunGlow)" />
      <circle cx="80" cy="195" r="50" fill="#facc15" stroke="#eab308" stroke-width="2" />
      <text x="80" y="201" text-anchor="middle" class="label" fill="#854d0e" font-size="16">SUN</text>
      <text x="260" y="105" text-anchor="middle" class="label" fill="#b45309">Sunlight Rays</text>
    </g>

    
    
    <g transform="rotate(23.5 480 195)">
      <line x1="480" y1="65" x2="480" y2="325" stroke="#64748b" stroke-width="2.5" stroke-dasharray="6 5" />
      
      <circle cx="480" cy="110" r="4.5" fill="#ef4444" stroke="#ffffff" stroke-width="1.5" />
      <circle cx="480" cy="280" r="4.5" fill="#ef4444" stroke="#ffffff" stroke-width="1.5" />
    </g>

    
    
    <g transform="translate(555, 60)">
      <text x="0" y="0" class="label">North Pole</text>
      <text x="0" y="16" class="label-muted">Axis (tilted 23.5°)</text>
    </g>
    
    <text x="410" y="352" text-anchor="end" class="label">South Pole</text>

    
    <g clip-path="url(#earthClip)">
      
      <circle cx="480" cy="195" r="85" fill="url(#earthDay)" />

      
      <g id="continentsGroup" transform="rotate(23.5 480 195)">
        
        <g id="landmasses" fill="#22c55e" opacity="0.92">
          
          <path d="M 80 145 q 25 -25 45 -10 t 25 30 t -20 35 t -40 -5 z M 95 205 q 30 -10 40 20 t -15 45 t -30 -15 z M 160 135 q 35 -20 60 10 t -20 40 t -40 -10 z M 175 210 q 25 -5 35 25 t -25 35 z" />
          
          <path d="M 280 145 q 25 -25 45 -10 t 25 30 t -20 35 t -40 -5 z M 295 205 q 30 -10 40 20 t -15 45 t -30 -15 z M 360 135 q 35 -20 60 10 t -20 40 t -40 -10 z M 375 210 q 25 -5 35 25 t -25 35 z" />
          
          <path d="M 480 145 q 25 -25 45 -10 t 25 30 t -20 35 t -40 -5 z M 495 205 q 30 -10 40 20 t -15 45 t -30 -15 z M 560 135 q 35 -20 60 10 t -20 40 t -40 -10 z M 575 210 q 25 -5 35 25 t -25 35 z" />
          
          <path d="M 680 145 q 25 -25 45 -10 t 25 30 t -20 35 t -40 -5 z M 695 205 q 30 -10 40 20 t -15 45 t -30 -15 z M 760 135 q 35 -20 60 10 t -20 40 t -40 -10 z M 775 210 q 25 -5 35 25 t -25 35 z" />
        </g>

        
        <line x1="370" y1="195" x2="590" y2="195" stroke="#ffffff" stroke-width="1.5" stroke-dasharray="3 3" opacity="0.45" />

        
        <g id="userMarker" transform="translate(480, 168)">
          <circle cx="0" cy="0" r="5.5" fill="#ef4444" stroke="#ffffff" stroke-width="2" />
          <text x="0" y="-9" text-anchor="middle" font-size="11" font-weight="bold" fill="#ffffff">📍 You</text>
        </g>
      </g>

      
      <circle cx="480" cy="195" r="85" fill="url(#nightShadow)" />

      
      <path d="M 480 110 A 85 85 0 0 0 480 280" fill="none" stroke="#93c5fd" stroke-width="4" opacity="0.5" />
    </g>

    
    <path d="M 412 195 A 72 22 0 0 0 548 195" fill="none" stroke="#0284c7" stroke-width="2.5" stroke-dasharray="5 3" marker-end="url(#arrow)" />
    <g transform="translate(480, 238)">
      <rect x="-72" y="-11" width="144" height="22" rx="11" fill="rgba(255, 255, 255, 0.95)" stroke="#cbd5e1" stroke-width="1" />
      <text x="0" y="4" text-anchor="middle" class="label" fill="#0369a1" font-size="11">Rotation (West to East)</text>
    </g>

    
    
    <g transform="translate(380, 308)">
      <rect x="-44" y="-13" width="88" height="26" rx="13" fill="#fef08a" stroke="#ca8a04" stroke-width="1.5" />
      <text x="0" y="5" text-anchor="middle" class="badge-text" fill="#854d0e">DAYTIME</text>
    </g>

    
    <g transform="translate(580, 308)">
      <rect x="-48" y="-13" width="96" height="26" rx="13" fill="#1e293b" stroke="#475569" stroke-width="1.5" />
      <text x="0" y="5" text-anchor="middle" class="badge-text" fill="#f8fafc">NIGHTTIME</text>
    </g>
  </svg>

  
  <div class="controls">
    <button id="playBtn" class="btn" aria-label="Toggle rotation animation">
      <span id="playIcon">⏸</span> <span id="playText">Pause</span>
    </button>
    <div id="statusBadge" class="status-badge">☀️ Midday (Day)</div>
  </div>
</div>

<script>
  let isPlaying = true;
  let offset = 0;
  let markerAngle = 0;
  const speed = 0.45;
  const period = 200; // continent repeat width

  const continents = document.getElementById('landmasses');
  const userMarker = document.getElementById('userMarker');
  const statusBadge = document.getElementById('statusBadge');
  const playBtn = document.getElementById('playBtn');
  const playIcon = document.getElementById('playIcon');
  const playText = document.getElementById('playText');

  function updateStatus(angleDeg) {
    const normalized = (angleDeg % 360 + 360) % 360;
    if (normalized >= 315 || normalized < 45) {
      statusBadge.textContent = "☀️ Midday (Day)";
      statusBadge.style.backgroundColor = "#fef08a";
      statusBadge.style.color = "#854d0e";
      statusBadge.style.borderColor = "#facc15";
    } else if (normalized >= 45 && normalized < 135) {
      statusBadge.textContent = "🌅 Sunset (Dusk)";
      statusBadge.style.backgroundColor = "#ffedd5";
      statusBadge.style.color = "#c2410c";
      statusBadge.style.borderColor = "#fdba74";
    } else if (normalized >= 135 && normalized < 225) {
      statusBadge.textContent = "🌙 Midnight (Night)";
      statusBadge.style.backgroundColor = "#1e293b";
      statusBadge.style.color = "#f8fafc";
      statusBadge.style.borderColor = "#475569";
    } else {
      statusBadge.textContent = "🌄 Sunrise (Dawn)";
      statusBadge.style.backgroundColor = "#e0f2fe";
      statusBadge.style.color = "#0369a1";
      statusBadge.style.borderColor = "#7dd3fc";
    }
  }

  function animate() {
    if (isPlaying) {
      offset = (offset + speed) % period;
      continents.setAttribute('transform', `translate(${offset - period}, 0)`);

      markerAngle = (markerAngle + (speed * (360 / period))) % 360;
      
      const rad = (markerAngle * Math.PI) / 180;
      const mx = 480 + Math.sin(rad) * 60;
      const my = 168 + Math.cos(rad) * 14;
      
      userMarker.setAttribute('transform', `translate(${mx}, ${my})`);
      
      // Reduce marker opacity when on far side of Earth
      const isBehind = Math.cos(rad) < -0.15;
      userMarker.setAttribute('opacity', isBehind ? '0.2' : '1');

      updateStatus(markerAngle);
    }
    requestAnimationFrame(animate);
  }

  playBtn.addEventListener('click', () => {
    isPlaying = !isPlaying;
    playIcon.textContent = isPlaying ? '⏸' : '▶';
    playText.textContent = isPlaying ? 'Pause' : 'Rotate Earth';
  });

  requestAnimationFrame(animate);
</script>

</body>
</html>

science.ks1.y1.t4.s2

Aligned learning resources

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