<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Gondwana Fossil Evidence</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    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;
      padding: 8px;
      user-select: none;
      -webkit-user-select: none;
      max-width: 600px;
      margin: 0 auto;
    }

    /* Fossil Filter Tabs */
    .filter-bar {
      display: flex;
      flex-wrap: wrap;
      gap: 5px;
      justify-content: center;
      width: 100%;
      margin-bottom: 8px;
    }

    .fossil-btn {
      appearance: none;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      padding: 5px 10px;
      border-radius: 16px;
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background-color 0.15s, color 0.15s, border-color 0.15s, opacity 0.15s;
    }

    .fossil-btn:hover {
      background: #f1f5f9;
      color: #0f172a;
    }

    .fossil-btn.active {
      color: #ffffff;
      border-color: transparent;
    }

    .fossil-btn[data-fossil="all"].active { background: #334155; }
    .fossil-btn[data-fossil="cynognathus"].active { background: #7c3aed; }
    .fossil-btn[data-fossil="mesosaurus"].active { background: #ea580c; }
    .fossil-btn[data-fossil="lystrosaurus"].active { background: #d97706; }
    .fossil-btn[data-fossil="glossopteris"].active { background: #15803d; }

    /* Map Stage */
    .map-container {
      position: relative;
      width: 100%;
      background: #e2f1fc;
      border-radius: 10px;
      overflow: hidden;
      box-shadow: inset 0 0 0 1px #bae6fd;
    }

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

    /* Landmass styling: neutral warm stone/tan for maximum contrast against all ribbon colors */
    .land {
      fill: #e8e2d8;
      stroke: #8d8070;
      stroke-width: 1.5;
      stroke-linejoin: round;
      stroke-linecap: round;
    }

    .land-label {
      font-size: 13px;
      font-weight: 800;
      fill: #292524;
      text-anchor: middle;
      pointer-events: none;
      paint-order: stroke fill;
      stroke: #ffffff;
      stroke-width: 3.5px;
      stroke-linejoin: round;
      letter-spacing: 0.2px;
    }

    .land-label-sub {
      font-size: 11px;
      font-weight: 700;
      fill: #44403c;
      text-anchor: middle;
      pointer-events: none;
      paint-order: stroke fill;
      stroke: #ffffff;
      stroke-width: 3px;
      stroke-linejoin: round;
    }

    /* Fossil Ribbons */
    .ribbon {
      fill: none;
      stroke-linecap: round;
      stroke-linejoin: round;
      cursor: pointer;
      opacity: 0.88;
      transition: opacity 0.2s, stroke-width 0.2s;
    }

    .ribbon:hover {
      opacity: 1;
    }

    .ribbon-cynognathus { stroke: #8b5cf6; stroke-width: 14; }
    .ribbon-mesosaurus  { stroke: #f97316; stroke-width: 13; }
    .ribbon-lystrosaurus { stroke: #eab308; stroke-width: 14; }
    .ribbon-glossopteris { stroke: #16a34a; stroke-width: 15; }

    /* Dimming & Highlighting */
    .dimmed {
      opacity: 0.12 !important;
    }
    .highlighted {
      opacity: 1 !important;
      filter: drop-shadow(0 0 3px rgba(0,0,0,0.45));
    }

    /* Info Card */
    .info-card {
      margin-top: 8px;
      width: 100%;
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 8px 12px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 8px;
      min-height: 44px;
    }

    .info-title {
      font-size: 13px;
      font-weight: 700;
      color: #0f172a;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .info-tag {
      font-size: 11px;
      font-weight: 600;
      padding: 3px 8px;
      border-radius: 12px;
      background: #f1f5f9;
      color: #475569;
      white-space: nowrap;
    }

    @media (max-width: 420px) {
      .fossil-btn {
        font-size: 11px;
        padding: 4px 8px;
      }
      .info-card {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        padding: 6px 10px;
      }
      .land-label {
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  
  <div class="filter-bar">
    <button class="fossil-btn active" data-fossil="all">✦ All Fossils</button>
    <button class="fossil-btn" data-fossil="cynognathus">🐾 Cynognathus</button>
    <button class="fossil-btn" data-fossil="mesosaurus">🐊 Mesosaurus</button>
    <button class="fossil-btn" data-fossil="lystrosaurus">🦛 Lystrosaurus</button>
    <button class="fossil-btn" data-fossil="glossopteris">🌿 Glossopteris</button>
  </div>

  
  <div class="map-container">
    <svg viewBox="0 0 560 380" aria-label="Map of Gondwana fossil bands">
      <defs>
        
        <pattern id="waves" width="24" height="24" patternUnits="userSpaceOnUse">
          <path d="M 0 12 Q 6 8 12 12 T 24 12" fill="none" stroke="#bae6fd" stroke-width="1.2" opacity="0.65"/>
        </pattern>
      </defs>

      
      <rect width="100%" height="100%" fill="url(#waves)"/>

      
      <g id="landmasses">
        
        <path class="land" id="land-sa" d="
          M 115,75
          C 135,70 162,72 178,92
          C 188,105 198,118 202,142
          C 207,170 205,198 188,225
          C 174,248 152,275 132,298
          C 120,312 112,308 108,290
          C 102,260 108,230 102,198
          C 96,168 85,148 88,122
          C 90,95 100,80 115,75 Z" />

        
        <path class="land" id="land-africa" d="
          M 180,95
          C 200,68 238,55 285,55
          C 328,55 350,78 355,108
          C 360,132 372,148 358,180
          C 345,210 338,235 305,262
          C 285,278 262,272 245,255
          C 225,238 206,230 190,222
          C 204,195 208,168 202,142
          C 196,120 188,106 180,95 Z" />

        
        <path class="land" id="land-madagascar" d="
          M 332,216
          C 342,212 346,225 342,242
          C 338,252 332,250 330,238
          C 328,226 326,218 332,216 Z" />

        
        <path class="land" id="land-india" d="
          M 346,148
          C 375,142 396,158 392,185
          C 388,212 368,232 348,232
          C 342,215 342,195 344,175
          C 345,160 342,152 346,148 Z" />

        
        <path class="land" id="land-antarctica" d="
          M 205,275
          C 230,270 258,265 295,268
          C 335,270 380,260 415,258
          C 455,258 485,282 485,320
          C 485,348 438,368 375,368
          C 305,368 240,358 195,330
          C 168,312 178,285 205,275 Z" />

        
        <path class="land" id="land-australia" d="
          M 425,195
          C 458,165 505,170 535,200
          C 552,220 545,265 530,285
          C 505,315 460,305 435,290
          C 418,278 412,245 418,225
          C 422,212 420,202 425,195 Z" />
      </g>

      
      <g id="ribbons">
        
        <path id="rib-glossopteris-1" class="ribbon ribbon-glossopteris" data-fossil="glossopteris"
              d="M 112,275 C 160,286 242,298 335,288 C 405,280 460,275 510,248" />
        <path id="rib-glossopteris-2" class="ribbon ribbon-glossopteris" data-fossil="glossopteris"
              d="M 335,288 C 348,255 358,225 365,185" />

        
        <path id="rib-cynognathus" class="ribbon ribbon-cynognathus" data-fossil="cynognathus"
              d="M 115,168 C 150,158 198,155 255,162 C 285,168 312,180 330,192" />

        
        <path id="rib-lystrosaurus-1" class="ribbon ribbon-lystrosaurus" data-fossil="lystrosaurus"
              d="M 270,202 C 300,205 334,192 362,175" />
        <path id="rib-lystrosaurus-2" class="ribbon ribbon-lystrosaurus" data-fossil="lystrosaurus"
              d="M 285,212 C 310,238 342,258 388,266" />

        
        <path id="rib-mesosaurus" class="ribbon ribbon-mesosaurus" data-fossil="mesosaurus"
              d="M 128,242 C 165,236 200,234 235,242 C 255,246 270,250 282,254" />
      </g>

      
      <text x="145" y="145" class="land-label">South America</text>
      <text x="272" y="128" class="land-label">Africa</text>
      <text x="368" y="196" class="land-label-sub">India</text>
      <text x="315" y="330" class="land-label">Antarctica</text>
      <text x="478" y="240" class="land-label">Australia</text>
    </svg>
  </div>

  
  <div class="info-card" id="infoCard">
    <div class="info-title" id="fossilTitle">✦ Southern Pangaea (Gondwana)</div>
    <span class="info-tag" id="fossilHabitat">Matched Fossil Bands</span>
  </div>

  <script>
    const fossilData = {
      all: {
        title: '✦ Southern Pangaea (Gondwana)',
        habitat: 'Matched Fossil Bands across continuous land'
      },
      cynognathus: {
        title: '🐾 Cynognathus',
        habitat: 'Land reptile/predator (cannot swim oceans)'
      },
      mesosaurus: {
        title: '🐊 Mesosaurus',
        habitat: 'Freshwater reptile only (cannot cross saltwater)'
      },
      lystrosaurus: {
        title: '🦛 Lystrosaurus',
        habitat: 'Land herbivore (cannot swim oceans)'
      },
      glossopteris: {
        title: '🌿 Glossopteris',
        habitat: 'Heavy-seeded subpolar tree/fern'
      }
    };

    const buttons = document.querySelectorAll('.fossil-btn');
    const ribbons = document.querySelectorAll('.ribbon');
    const titleEl = document.getElementById('fossilTitle');
    const tagEl = document.getElementById('fossilHabitat');

    function selectFossil(fossilKey) {
      buttons.forEach(btn => {
        btn.classList.toggle('active', btn.dataset.fossil === fossilKey);
      });

      ribbons.forEach(rib => {
        const isMatch = rib.dataset.fossil === fossilKey;
        if (fossilKey === 'all') {
          rib.classList.remove('dimmed', 'highlighted');
        } else if (isMatch) {
          rib.classList.remove('dimmed');
          rib.classList.add('highlighted');
        } else {
          rib.classList.add('dimmed');
          rib.classList.remove('highlighted');
        }
      });

      const data = fossilData[fossilKey] || fossilData.all;
      titleEl.textContent = data.title;
      tagEl.textContent = data.habitat;
    }

    buttons.forEach(btn => {
      btn.addEventListener('click', () => selectFossil(btn.dataset.fossil));
    });

    ribbons.forEach(rib => {
      rib.addEventListener('click', () => selectFossil(rib.dataset.fossil));
      rib.addEventListener('mouseenter', () => selectFossil(rib.dataset.fossil));
    });
  </script>
</body>
</html>

Evidence for Continental Drift: Fossils, Rocks, and Coastlines

<!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">
  <script src="{{VENDOR_CDN}}/classace-diagram.js"></script>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    html, body {
      width: 100%;
      height: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 10px 12px;
      user-select: none;
      overflow: hidden;
    }

    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      z-index: 10;
      flex-wrap: wrap;
      justify-content: center;
    }

    .btn-step {
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 8px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 6px;
      transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
    }

    .btn-step:hover {
      border-color: #94a3b8;
      background: #f1f5f9;
    }

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

    .step-num {
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: rgba(0,0,0,0.08);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 11px;
    }
    .btn-step.active .step-num {
      background: rgba(255,255,255,0.25);
    }

    .play-btn {
      width: 32px;
      height: 32px;
      border-radius: 8px;
      border: 1.5px solid #cbd5e1;
      background: #ffffff;
      color: #334155;
      font-size: 13px;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: background 0.2s ease, border-color 0.2s ease;
    }

    .play-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .svg-container {
      width: 100%;
      flex: 1;
      max-width: 580px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      min-height: 0;
    }

    svg {
      width: 100%;
      height: 100%;
      max-height: 340px;
      overflow: visible;
    }

    /* Continent group animations */
    .plate-na {
      transition: transform 1.2s cubic-bezier(0.4, 0, 0.2, 1);
      transform: translate(0px, 0px);
    }
    .plate-eu {
      transition: transform 1.2s cubic-bezier(0.4, 0, 0.2, 1);
      transform: translate(0px, 0px);
    }

    /* Perfect seamless continental match */
    .joined .plate-na {
      transform: translate(75px, 0px);
    }
    .joined .plate-eu {
      transform: translate(-75px, 0px);
    }

    /* Ocean label & cues fade */
    .ocean-cue {
      transition: opacity 0.8s ease;
      opacity: 1;
    }
    .joined .ocean-cue {
      opacity: 0;
      pointer-events: none;
    }

    /* Mountain styling */
    .mountain-band-glow {
      stroke: #ea580c;
      stroke-width: 18;
      stroke-linecap: round;
      stroke-linejoin: round;
      fill: none;
      opacity: 0.25;
      transition: stroke 0.6s ease, opacity 0.6s ease;
    }
    .joined .mountain-band-glow {
      stroke: #f97316;
      opacity: 0.55;
    }

    .mountain-band {
      stroke: #c2410c;
      stroke-width: 11;
      stroke-linecap: round;
      stroke-linejoin: round;
      fill: none;
    }

    .mountain-ridge {
      stroke: #fef08a;
      stroke-width: 2.5;
      stroke-linecap: round;
      stroke-linejoin: round;
      stroke-dasharray: 4 4;
      fill: none;
    }

    .plate-body {
      fill: #cbd5e1;
      stroke: #64748b;
      stroke-width: 2;
      stroke-linejoin: round;
      transition: fill 0.8s ease;
    }
    .joined .plate-body {
      fill: #cbd5e1;
    }

    /* Typography */
    .continent-label {
      font-size: 13px;
      font-weight: 700;
      fill: #1e293b;
      text-anchor: middle;
      paint-order: stroke;
      stroke: #ffffff;
      stroke-width: 3.5px;
      stroke-linejoin: round;
    }

    .mountain-label {
      font-size: 11.5px;
      font-weight: 700;
      fill: #9a3412;
      paint-order: stroke;
      stroke: #ffffff;
      stroke-width: 3.5px;
      stroke-linejoin: round;
    }

    .ocean-text {
      font-size: 11px;
      font-weight: 700;
      fill: #0284c7;
      letter-spacing: 1.5px;
      text-anchor: middle;
      paint-order: stroke;
      stroke: #f0f9ff;
      stroke-width: 3px;
    }

    .badge-joined {
      transition: opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1), transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
      opacity: 0;
      transform: translateY(6px);
      pointer-events: none;
    }
    .joined .badge-joined {
      opacity: 1;
      transform: translateY(0);
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button id="btn1" class="btn-step active" onclick="setStep(0)">
      <span class="step-num">1</span> Modern Continents
    </button>
    <button id="btn2" class="btn-step" onclick="setStep(1)">
      <span class="step-num">2</span> Pangaea (~300 Mya)
    </button>
    <button id="playBtn" class="play-btn" title="Toggle autoplay">⏸</button>
  </div>

  
  <div class="svg-container">
    <svg id="stage" viewBox="0 0 540 320">
      <defs>
        
        <linearGradient id="oceanGrad" x1="0%" y1="0%" x2="0%" y2="100%">
          <stop offset="0%" stop-color="#e0f2fe" />
          <stop offset="100%" stop-color="#bae6fd" />
        </linearGradient>

        <filter id="plateShadow" x="-10%" y="-10%" width="125%" height="125%">
          <feDropShadow dx="0" dy="3" stdDeviation="3" flood-color="#0f172a" flood-opacity="0.14" />
        </filter>

        <marker id="arrowL" markerWidth="6" markerHeight="6" refX="2" refY="3" orient="auto">
          <path d="M5,1 L1,3 L5,5" fill="none" stroke="#0284c7" stroke-width="1.5" stroke-linecap="round" />
        </marker>
        <marker id="arrowR" markerWidth="6" markerHeight="6" refX="4" refY="3" orient="auto">
          <path d="M1,1 L5,3 L1,5" fill="none" stroke="#0284c7" stroke-width="1.5" stroke-linecap="round" />
        </marker>
      </defs>

      
      <rect width="540" height="320" fill="url(#oceanGrad)" rx="12" />

      
      <g class="ocean-cue">
        <path d="M 270 45 C 260 110, 280 190, 270 265" stroke="#7dd3fc" stroke-width="38" stroke-linecap="round" fill="none" opacity="0.6" />
        <text x="270" y="148" class="ocean-text">ATLANTIC OCEAN</text>
        <line x1="218" y1="166" x2="238" y2="166" stroke="#0284c7" stroke-width="1.5" marker-start="url(#arrowL)" stroke-linecap="round" />
        <line x1="302" y1="166" x2="322" y2="166" stroke="#0284c7" stroke-width="1.5" marker-end="url(#arrowR)" stroke-linecap="round" />
        <text x="270" y="186" fill="#0369a1" font-size="9.5" font-weight="600" text-anchor="middle">Separated by plate tectonics</text>
      </g>

      
      <g id="naPlate" class="plate-na" filter="url(#plateShadow)">
        
        <path class="plate-body" d="M 50 55 
                 C 90 40, 140 42, 195 50 
                 C 190 95, 195 140, 190 185 
                 C 185 220, 195 240, 190 265 
                 C 140 275, 90 270, 55 245 
                 C 30 200, 25 120, 50 55 Z" />
        
        
        <path d="M 75 235 C 115 190, 155 145, 190 95" class="mountain-band-glow" />
        <path d="M 75 235 C 115 190, 155 145, 190 95" class="mountain-band" />
        <path d="M 75 235 C 115 190, 155 145, 190 95" class="mountain-ridge" />

        
        <text x="100" y="95" class="continent-label">North America</text>
        
        <g transform="translate(62, 168)">
          <rect x="-4" y="-12" width="76" height="17" rx="4" fill="#ffffff" fill-opacity="0.85" />
          <text x="34" y="0" text-anchor="middle" class="mountain-label">Appalachians</text>
        </g>
      </g>

      
      <g id="euPlate" class="plate-eu" filter="url(#plateShadow)">
        
        <path class="plate-body" d="M 345 50 
                 C 390 35, 450 35, 485 70 
                 C 515 110, 495 195, 475 235 
                 C 435 270, 390 270, 340 265 
                 C 345 240, 335 220, 340 185 
                 C 345 140, 340 95, 345 50 Z" />

        
        <path d="M 340 95 C 385 70, 425 55, 465 48" class="mountain-band-glow" />
        <path d="M 340 95 C 385 70, 425 55, 465 48" class="mountain-band" />
        <path d="M 340 95 C 385 70, 425 55, 465 48" class="mountain-ridge" />

        
        <text x="420" y="165" class="continent-label">Eurasia &amp; Greenland</text>
        
        <g transform="translate(385, 102)">
          <rect x="-4" y="-12" width="76" height="17" rx="4" fill="#ffffff" fill-opacity="0.85" />
          <text x="34" y="0" text-anchor="middle" class="mountain-label">Caledonides</text>
        </g>
      </g>

      
      <g class="badge-joined">
        <rect x="135" y="276" width="270" height="30" rx="15" fill="#7c2d12" stroke="#fed7aa" stroke-width="1.5" filter="url(#plateShadow)" />
        <text x="270" y="295" fill="#ffffff" font-size="11" font-weight="700" text-anchor="middle" letter-spacing="0.4px">
          ✦ One Continuous Mountain Chain ✦
        </text>
      </g>
    </svg>
  </div>

  <script>
    const stage = document.getElementById('stage');
    const btn1 = document.getElementById('btn1');
    const btn2 = document.getElementById('btn2');
    const playBtn = document.getElementById('playBtn');

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

    function setStep(index) {
      currentStep = index;
      if (currentStep === 1) {
        stage.classList.add('joined');
        btn1.classList.remove('active');
        btn2.classList.add('active');
      } else {
        stage.classList.remove('joined');
        btn2.classList.remove('active');
        btn1.classList.add('active');
      }
    }

    function togglePlay() {
      autoPlay = !autoPlay;
      playBtn.textContent = autoPlay ? '⏸' : '▶';
      if (autoPlay) {
        runLoop();
      } else {
        clearTimeout(timer);
      }
    }

    function runLoop() {
      clearTimeout(timer);
      if (!autoPlay) return;
      timer = setTimeout(() => {
        setStep((currentStep + 1) % 2);
        runLoop();
      }, 3400);
    }

    playBtn.addEventListener('click', togglePlay);
    runLoop();
  </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>Glacial Evidence for Pangaea</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: transparent;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      width: 100%;
      min-height: 100vh;
      padding: 10px;
    }

    .diagram-container {
      width: 100%;
      max-width: 680px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .diagram-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      width: 100%;
    }

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

    .panel {
      display: flex;
      flex-direction: column;
      align-items: center;
      width: 100%;
    }

    .panel-header {
      text-align: center;
      margin-bottom: 6px;
    }

    .panel-title {
      font-size: 13px;
      font-weight: 700;
      letter-spacing: 0.2px;
    }

    .panel-subtitle {
      font-size: 11px;
      color: #64748b;
      margin-top: 1px;
    }

    .badge-modern { color: #d97706; }
    .badge-pangaea { color: #0284c7; }

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

    .land-mass {
      fill: #cbd5e1;
      stroke: #94a3b8;
      stroke-width: 1.5;
    }

    .label-main {
      font-size: 11px;
      font-weight: 700;
      fill: #334155;
      paint-order: stroke;
      stroke: #ffffff;
      stroke-width: 2.5px;
      stroke-linecap: round;
      stroke-linejoin: round;
    }

    .ice-pulse {
      animation: pulseIce 3s ease-in-out infinite;
      transform-origin: 150px 145px;
    }

    @keyframes pulseIce {
      0%, 100% { opacity: 0.45; }
      50% { opacity: 0.75; }
    }

    .arrow-flow {
      stroke-dasharray: 6 3;
      animation: dashFlow 2s linear infinite;
    }

    @keyframes dashFlow {
      to { stroke-dashoffset: -18; }
    }

    .legend-bar {
      display: flex;
      justify-content: center;
      gap: 16px;
      font-size: 11px;
      color: #475569;
      font-weight: 600;
      margin-top: 4px;
      flex-wrap: wrap;
    }

    .legend-item {
      display: flex;
      align-items: center;
      gap: 5px;
    }

    .dot-ice {
      width: 10px;
      height: 10px;
      background: #7dd3fc;
      border: 1px solid #0284c7;
      border-radius: 2px;
    }

    .line-flow-red {
      width: 14px;
      height: 2px;
      background: #ef4444;
    }

    .line-flow-blue {
      width: 14px;
      height: 2px;
      background: #0284c7;
    }
  </style>
</head>
<body>

  <div class="diagram-container">
    <div class="diagram-grid">
      
      <div class="panel">
        <div class="panel-header">
          <div class="panel-title badge-modern">Modern Map</div>
          <div class="panel-subtitle">Unexplained glacial striations in warm zones</div>
        </div>
        <svg viewBox="0 0 300 205" xmlns="http://www.w3.org/2000/svg">
          <defs>
            <marker id="arrow-confused" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="5" markerHeight="5" orient="auto-start-reverse">
              <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#ef4444" />
            </marker>
          </defs>

          
          <rect x="5" y="45" width="290" height="55" fill="#fef3c7" opacity="0.45" rx="4" />
          <text x="12" y="58" font-size="10" fill="#b45309" font-weight="700">Warm Tropics</text>

          
          <line x1="5" y1="72" x2="295" y2="72" stroke="#94a3b8" stroke-width="1.2" stroke-dasharray="4 3" />
          <text x="248" y="68" font-size="9.5" fill="#64748b" font-weight="600">Equator</text>

          
          <path d="M 42,75 Q 64,75 62,105 Q 52,145 42,165 Q 33,155 30,110 Q 28,85 42,75 Z" class="land-mass" />
          <text x="14" y="118" class="label-main">S. America</text>
          
          <path d="M 40,130 Q 53,128 50,155 Q 38,160 40,130 Z" fill="#bae6fd" stroke="#0284c7" stroke-width="1" />
          <line x1="53" y1="150" x2="40" y2="134" stroke="#ef4444" stroke-width="2" marker-end="url(#arrow-confused)" />

          
          <path d="M 100,55 Q 140,55 140,85 Q 134,115 122,148 Q 106,152 98,130 Q 90,95 100,55 Z" class="land-mass" />
          <text x="110" y="88" class="label-main">Africa</text>
          
          <path d="M 105,122 Q 122,122 119,145 Q 107,148 105,122 Z" fill="#bae6fd" stroke="#0284c7" stroke-width="1" />
          <line x1="122" y1="142" x2="108" y2="125" stroke="#ef4444" stroke-width="2" marker-end="url(#arrow-confused)" />

          
          <path d="M 172,60 L 193,65 L 186,92 Z" class="land-mass" />
          <text x="195" y="78" class="label-main">India</text>
          
          <path d="M 177,72 L 188,75 L 184,88 Z" fill="#bae6fd" stroke="#0284c7" stroke-width="1" />
          <line x1="184" y1="90" x2="180" y2="72" stroke="#ef4444" stroke-width="2" marker-end="url(#arrow-confused)" />

          
          <path d="M 226,115 Q 264,115 264,142 Q 248,165 224,152 Q 216,130 226,115 Z" class="land-mass" />
          <text x="228" y="132" class="label-main">Australia</text>
          
          <path d="M 226,135 Q 244,132 241,152 Q 226,152 226,135 Z" fill="#bae6fd" stroke="#0284c7" stroke-width="1" />
          <line x1="246" y1="148" x2="230" y2="132" stroke="#ef4444" stroke-width="2" marker-end="url(#arrow-confused)" />

          
          <path d="M 105,182 Q 155,172 205,182 Q 180,200 130,200 Z" class="land-mass" fill="#e2e8f0" />
          <text x="155" y="193" font-size="10.5" font-weight="700" fill="#475569" text-anchor="middle">Antarctica</text>
        </svg>
      </div>

      
      <div class="panel">
        <div class="panel-header">
          <div class="panel-title badge-pangaea">Pangaea Reassembled</div>
          <div class="panel-subtitle">Single ice sheet radiating away from South Pole</div>
        </div>
        <svg viewBox="0 0 300 205" xmlns="http://www.w3.org/2000/svg">
          <defs>
            <marker id="arrow-unified" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="5" markerHeight="5" orient="auto-start-reverse">
              <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#0284c7" />
            </marker>
          </defs>

          
          
          <path d="M 85,98 Q 112,100 118,126 Q 105,168 75,173 Q 68,138 85,98 Z" class="land-mass" />
          
          
          <path d="M 120,50 Q 160,60 165,93 Q 160,136 135,156 Q 116,126 120,50 Z" class="land-mass" />

          
          <path d="M 166,98 L 190,110 L 168,133 Z" class="land-mass" />

          
          <path d="M 115,153 Q 155,138 190,153 Q 185,193 125,193 Z" class="land-mass" />

          
          <path d="M 188,140 Q 228,128 235,158 Q 212,183 186,170 Z" class="land-mass" />

          
          <circle cx="150" cy="143" r="44" fill="#38bdf8" class="ice-pulse" />
          <circle cx="150" cy="143" r="44" fill="none" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="4 2" />

          
          <text x="50" y="112" class="label-main">S. America</text>
          <text x="142" y="78" class="label-main">Africa</text>
          <text x="195" y="105" class="label-main">India</text>
          <text x="212" y="148" class="label-main">Australia</text>
          <text x="155" y="185" class="label-main" text-anchor="middle">Antarctica</text>

          
          
          <line x1="145" y1="133" x2="136" y2="106" stroke="#0284c7" stroke-width="2.5" class="arrow-flow" marker-end="url(#arrow-unified)" />
          
          <line x1="140" y1="143" x2="105" y2="130" stroke="#0284c7" stroke-width="2.5" class="arrow-flow" marker-end="url(#arrow-unified)" />
          
          <line x1="160" y1="136" x2="182" y2="116" stroke="#0284c7" stroke-width="2.5" class="arrow-flow" marker-end="url(#arrow-unified)" />
          
          <line x1="163" y1="148" x2="207" y2="146" stroke="#0284c7" stroke-width="2.5" class="arrow-flow" marker-end="url(#arrow-unified)" />

          
          <circle cx="150" cy="143" r="3.5" fill="#0369a1" />
          <text x="150" y="138" font-size="9" font-weight="800" fill="#0369a1" text-anchor="middle" style="paint-order: stroke; stroke: #ffffff; stroke-width: 2px;">South Pole</text>

          
          <text x="150" y="201" font-size="10.5" font-weight="700" fill="#0284c7" text-anchor="middle">Single Unified Ice Sheet ❄️</text>
        </svg>
      </div>
    </div>

    
    <div class="legend-bar">
      <div class="legend-item">
        <div class="dot-ice"></div>
        <span>Glacial deposit</span>
      </div>
      <div class="legend-item">
        <div class="line-flow-red"></div>
        <span>Inconsistent modern flow</span>
      </div>
      <div class="legend-item">
        <div class="line-flow-blue"></div>
        <span>Consistent Pangaea flow</span>
      </div>
    </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">
  <title>Continental Drift - Jigsaw Fit</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #0f172a;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      padding: 10px;
      gap: 10px;
    }

    .main-container {
      width: 100%;
      max-width: 640px;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .canvas-wrapper {
      position: relative;
      width: 100%;
      aspect-ratio: 16 / 10;
      background: #dbeafe;
      border-radius: 8px;
      overflow: hidden;
    }

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

    .ocean-label {
      position: absolute;
      top: 48%;
      left: 44%;
      transform: translate(-50%, -50%);
      font-size: clamp(10px, 2.4vw, 13px);
      font-weight: 700;
      color: #0284c7;
      letter-spacing: 2px;
      text-transform: uppercase;
      pointer-events: none;
      transition: opacity 0.35s ease;
      white-space: nowrap;
    }

    .continent-sa {
      cursor: grab;
      filter: drop-shadow(0 3px 6px rgba(15, 23, 42, 0.18));
      touch-action: none;
    }
    .continent-sa:active {
      cursor: grabbing;
    }

    .shelf-glow {
      fill: none;
      stroke: #38bdf8;
      stroke-width: 6px;
      stroke-linecap: round;
      filter: drop-shadow(0 0 10px #0284c7);
      opacity: 0;
      transition: opacity 0.35s ease;
      pointer-events: none;
    }

    .evidence-fossil {
      fill: none;
      stroke: #ea580c;
      stroke-width: 6;
      stroke-linecap: round;
      stroke-dasharray: 4 2;
      opacity: 0.9;
    }

    .evidence-mountain {
      fill: none;
      stroke: #7c3aed;
      stroke-width: 6;
      stroke-linecap: round;
      stroke-dasharray: 4 2;
      opacity: 0.9;
    }

    .evidence-plant {
      fill: none;
      stroke: #16a34a;
      stroke-width: 6;
      stroke-linecap: round;
      stroke-dasharray: 4 2;
      opacity: 0.9;
    }

    /* Legend */
    .legend-bar {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: center;
      gap: 8px 16px;
      font-size: 11px;
      font-weight: 600;
      color: #475569;
    }

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

    .legend-line {
      width: 16px;
      height: 4px;
      border-radius: 2px;
    }

    /* Controls */
    .controls {
      display: flex;
      flex-direction: column;
      gap: 8px;
      width: 100%;
    }

    .slider-row {
      display: flex;
      align-items: center;
      gap: 10px;
      width: 100%;
    }

    .slider-label {
      font-size: 12px;
      font-weight: 700;
      color: #475569;
      white-space: nowrap;
      min-width: 55px;
    }
    .slider-label.right {
      text-align: right;
    }

    input[type=range] {
      flex: 1;
      accent-color: #0284c7;
      height: 6px;
      cursor: pointer;
    }

    .btn-row {
      display: flex;
      justify-content: center;
      gap: 10px;
    }

    button {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      padding: 7px 15px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 600;
      color: #334155;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
    }

    button:hover {
      background: #f1f5f9;
    }

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

    .hint-text {
      text-align: center;
      font-size: 11px;
      color: #64748b;
    }
  </style>
</head>
<body>

  <div class="main-container">
    <div class="canvas-wrapper" id="canvasWrapper">
      <div class="ocean-label" id="oceanLabel">Atlantic Ocean</div>

      <svg viewBox="0 0 650 390">
        <defs>
          
          <pattern id="grid" width="30" height="30" patternUnits="userSpaceOnUse">
            <path d="M 30 0 L 0 0 0 30" fill="none" stroke="#bae6fd" stroke-width="0.5" stroke-opacity="0.6"/>
          </pattern>
        </defs>

        <rect width="100%" height="100%" fill="url(#grid)" />

        
        <path d="M 270 20 Q 295 120 270 200 T 285 380" fill="none" stroke="#93c5fd" stroke-width="2" stroke-dasharray="4 4" opacity="0.7"/>

        
        <g id="africa">
          
          <path d="
            M 315,48
            C 345,35 390,32 430,42
            C 465,50 490,56 505,74
            C 520,95 538,122 558,145
            C 564,158 556,176 538,198
            C 520,222 502,255 488,290
            C 472,328 450,358 426,370
            C 408,376 394,374 382,365
            C 370,335 362,290 356,255
            C 348,222 332,198 310,192
            C 285,188 268,175 250,158
            C 238,136 242,106 255,80
            C 270,58 292,52 315,48 Z"
            fill="#f8fafc" stroke="#334155" stroke-width="2" stroke-linejoin="round" />

          
          
          <path d="M 378,350 Q 398,358 420,360" class="evidence-mountain" />
          
          <path d="M 360,270 Q 395,280 435,285" class="evidence-fossil" />
          
          <path d="M 325,205 Q 380,215 445,210" class="evidence-plant" />

          
          <text x="415" y="125" font-size="13" font-weight="700" fill="#1e293b" text-anchor="middle" letter-spacing="0.8">AFRICA</text>
        </g>

        
        <g id="southAmerica" class="continent-sa">
          <g id="saGroup">
            
            <path d="
              M 195,75
              C 220,58 250,56 280,68
              C 305,78 328,102 342,130
              C 352,152 342,170 310,192
              C 332,198 348,222 356,255
              C 362,290 370,335 382,365
              C 375,376 360,378 348,368
              C 335,345 320,305 305,255
              C 290,210 268,175 240,150
              C 205,122 178,110 172,96
              C 168,84 180,78 195,75 Z"
              fill="#e2e8f0" stroke="#334155" stroke-width="2" stroke-linejoin="round" />

            
            
            <path d="M 342,342 Q 362,347 378,350" class="evidence-mountain" />
            
            <path d="M 310,260 Q 338,265 360,270" class="evidence-fossil" />
            
            <path d="M 260,195 Q 295,200 325,205" class="evidence-plant" />

            
            <text x="260" y="128" font-size="11" font-weight="700" fill="#1e293b" text-anchor="middle" letter-spacing="0.6">
              <tspan x="260" dy="0">SOUTH</tspan>
              <tspan x="260" dy="14">AMERICA</tspan>
            </text>
          </g>
        </g>

        
        <path id="glowSeam" class="shelf-glow" d="
          M 250,158
          C 268,175 285,188 310,192
          C 332,198 348,222 356,255
          C 362,290 370,335 382,365" />
      </svg>
    </div>

    
    <div class="legend-bar">
      <div class="legend-item">
        <span class="legend-line" style="background:#ea580c;"></span>
        <span>Mesosaurus fossils</span>
      </div>
      <div class="legend-item">
        <span class="legend-line" style="background:#16a34a;"></span>
        <span>Glossopteris flora</span>
      </div>
      <div class="legend-item">
        <span class="legend-line" style="background:#7c3aed;"></span>
        <span>Matching mountain belts</span>
      </div>
    </div>

    
    <div class="controls">
      <div class="slider-row">
        <span class="slider-label">Modern</span>
        <input type="range" id="driftSlider" min="0" max="100" value="0" aria-label="Continental Drift Slider">
        <span class="slider-label right">Pangaea</span>
      </div>
      <div class="btn-row">
        <button id="btnModern" class="active" type="button">Modern Map</button>
        <button id="btnFit" type="button">Jigsaw Fit (250 Mya) ✦</button>
      </div>
      <div class="hint-text">Drag South America or use the slider to test the continental fit</div>
    </div>
  </div>

  <script>
    const slider = document.getElementById('driftSlider');
    const saGroup = document.getElementById('saGroup');
    const oceanLabel = document.getElementById('oceanLabel');
    const glowSeam = document.getElementById('glowSeam');
    const btnModern = document.getElementById('btnModern');
    const btnFit = document.getElementById('btnFit');
    const saElement = document.getElementById('southAmerica');

    // Translation parameters for realistic continental drift alignment
    const MODERN_OFFSET_X = -135;
    const MODERN_OFFSET_Y = -8;
    const MODERN_ROTATION = -3.5;

    function updatePositions(progress) {
      const p = Math.max(0, Math.min(100, progress)) / 100;
      
      // Smooth interpolation from modern separated view (p=0) to Pangaea fit (p=1)
      const currentX = (1 - p) * MODERN_OFFSET_X;
      const currentY = (1 - p) * MODERN_OFFSET_Y;
      const currentRot = (1 - p) * MODERN_ROTATION;

      // Transform South America relative to the fit pivot along the coastal curve
      saGroup.setAttribute('transform', `translate(${currentX}, ${currentY}) rotate(${currentRot}, 310, 192)`);

      // Atlantic Ocean label fades as the ocean basin closes
      oceanLabel.style.opacity = Math.max(0, 1 - p * 1.5);

      // Continental shelf match glows when puzzle pieces align
      if (p > 0.85) {
        const glowOpacity = (p - 0.85) / 0.15;
        glowSeam.style.opacity = glowOpacity;
      } else {
        glowSeam.style.opacity = 0;
      }

      // Update button active state
      if (p <= 0.05) {
        btnModern.classList.add('active');
        btnFit.classList.remove('active');
      } else if (p >= 0.95) {
        btnFit.classList.add('active');
        btnModern.classList.remove('active');
      } else {
        btnModern.classList.remove('active');
        btnFit.classList.remove('active');
      }
    }

    slider.addEventListener('input', (e) => {
      updatePositions(parseFloat(e.target.value));
    });

    let animFrame = null;
    function animateTo(targetVal) {
      if (animFrame) cancelAnimationFrame(animFrame);
      const startVal = parseFloat(slider.value);
      const startTime = performance.now();
      const duration = 550; // Smooth transition duration

      function step(now) {
        const elapsed = now - startTime;
        const t = Math.min(1, elapsed / duration);
        // Smooth cubic ease-in-out
        const ease = t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
        const current = startVal + (targetVal - startVal) * ease;
        slider.value = current;
        updatePositions(current);
        if (t < 1) {
          animFrame = requestAnimationFrame(step);
        }
      }
      animFrame = requestAnimationFrame(step);
    }

    btnModern.addEventListener('click', () => animateTo(0));
    btnFit.addEventListener('click', () => animateTo(100));

    // Interactive pointer drag directly on South America
    let isDragging = false;
    let startPointerX = 0;
    let startProgress = 0;

    function onPointerDown(e) {
      if (animFrame) cancelAnimationFrame(animFrame);
      isDragging = true;
      startPointerX = e.clientX;
      startProgress = parseFloat(slider.value);
      window.addEventListener('pointermove', onPointerMove);
      window.addEventListener('pointerup', onPointerUp);
      window.addEventListener('pointercancel', onPointerUp);
    }

    function onPointerMove(e) {
      if (!isDragging) return;
      const currentX = e.clientX;
      const deltaX = currentX - startPointerX;
      // 145px drag distance represents full closure
      const deltaPercent = (deltaX / 145) * 100;
      const newProgress = Math.max(0, Math.min(100, startProgress + deltaPercent));
      slider.value = newProgress;
      updatePositions(newProgress);
    }

    function onPointerUp() {
      isDragging = false;
      window.removeEventListener('pointermove', onPointerMove);
      window.removeEventListener('pointerup', onPointerUp);
      window.removeEventListener('pointercancel', onPointerUp);
    }

    saElement.addEventListener('pointerdown', onPointerDown);

    // Initialize in separated modern configuration
    updatePositions(0);
  </script>
</body>
</html>

OGS.7.ESS.2

Aligned learning resources

Related diagrams