<!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>Prism vs Pyramid</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      width: 100%;
      min-height: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
    }
    .controls {
      display: flex;
      gap: 8px;
      margin-bottom: 8px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .btn {
      background: #f1f5f9;
      border: 2px solid transparent;
      color: #475569;
      padding: 6px 14px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .btn.active {
      background: #e0f2fe;
      color: #0369a1;
      border-color: #0284c7;
    }
    .svg-container {
      width: 100%;
      max-width: 650px;
      height: auto;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }
    .shape-title {
      font-size: 17px;
      font-weight: 700;
      text-anchor: middle;
    }
    .prism-title { fill: #0284c7; }
    .pyramid-title { fill: #ea580c; }
    .feature-tag {
      font-size: 13.5px;
      font-weight: 600;
      text-anchor: middle;
    }
    .prism-tag { fill: #0369a1; }
    .pyramid-tag { fill: #c2410c; }
    .apex-text {
      font-size: 14px;
      font-weight: 700;
      fill: #ea580c;
      text-anchor: start;
    }
    .dimmed {
      opacity: 0.25 !important;
      transition: opacity 0.3s ease;
    }
    .highlighted {
      filter: drop-shadow(0 0 6px rgba(0,0,0,0.18));
      transition: all 0.3s ease;
    }
    polygon, line, path, circle {
      transition: opacity 0.3s ease, fill 0.3s ease, stroke 0.3s ease;
    }
  </style>
</head>
<body>

  <div class="controls">
    <button class="btn active" id="btn-all" onclick="setMode('all')">Compare All</button>
    <button class="btn" id="btn-bases" onclick="setMode('bases')">Highlight Bases</button>
    <button class="btn" id="btn-sides" onclick="setMode('sides')">Highlight Sides</button>
  </div>

  <div class="svg-container">
    <svg viewBox="0 0 650 380" aria-label="Triangular Prism vs Triangular Pyramid Comparison">
      
      <line x1="325" y1="20" x2="325" y2="360" stroke="#e2e8f0" stroke-width="2" stroke-dasharray="6,6" />

      
      <g id="prism-group">
        
        <text x="160" y="32" class="shape-title prism-title">Triangular Prism</text>
        <text x="160" y="358" class="feature-tag prism-tag">2 Matching Bases (Prism)</text>

        
        <line class="side-el" x1="165" y1="100" x2="165" y2="235" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="4,4" />
        <line class="base-el" x1="75" y1="260" x2="165" y2="235" stroke="#0099cc" stroke-width="2" stroke-dasharray="4,4" />
        <line class="base-el" x1="225" y1="280" x2="165" y2="235" stroke="#0099cc" stroke-width="2" stroke-dasharray="4,4" />
        <line class="base-el" x1="75" y1="125" x2="165" y2="100" stroke="#0099cc" stroke-width="2" stroke-dasharray="4,4" />
        <line class="base-el" x1="225" y1="145" x2="165" y2="100" stroke="#0099cc" stroke-width="2" stroke-dasharray="4,4" />

        
        <polygon class="base-el" points="75,260 225,280 165,235" fill="rgba(0, 210, 255, 0.4)" stroke="#00a8e8" stroke-width="2" />

        
        <polygon class="side-el" points="75,125 225,145 225,280 75,260" fill="rgba(2, 132, 199, 0.12)" stroke="#0284c7" stroke-width="2" />

        
        <polygon class="base-el" points="75,125 225,145 165,100" fill="rgba(0, 210, 255, 0.65)" stroke="#0088cc" stroke-width="2.5" />

        
        <line class="side-el" x1="75" y1="125" x2="75" y2="260" stroke="#0284c7" stroke-width="2.5" />
        <line class="side-el" x1="225" y1="145" x2="225" y2="280" stroke="#0284c7" stroke-width="2.5" />

        
        <g class="base-el">
          <rect x="180" y="80" width="85" height="22" rx="11" fill="#e0f2fe" />
          <text x="222" y="95" font-size="11.5" font-weight="700" fill="#0369a1" text-anchor="middle">Top Base ▲</text>

          <rect x="180" y="292" width="95" height="22" rx="11" fill="#e0f2fe" />
          <text x="227" y="307" font-size="11.5" font-weight="700" fill="#0369a1" text-anchor="middle">Bottom Base ▲</text>
        </g>
        
        
        <g class="side-el">
          <rect x="35" y="185" width="86" height="22" rx="11" fill="#f8fafc" stroke="#cbd5e1" stroke-width="1" />
          <text x="78" y="200" font-size="11" font-weight="600" fill="#475569" text-anchor="middle">3 Rectangles</text>
        </g>
      </g>

      
      <g id="pyramid-group">
        
        <text x="490" y="32" class="shape-title pyramid-title">Triangular Pyramid</text>
        <text x="490" y="358" class="feature-tag pyramid-tag">1 Base + Pointy Top (Pyramid)</text>

        
        <line class="base-el" x1="410" y1="270" x2="495" y2="225" stroke="#e65100" stroke-width="2" stroke-dasharray="4,4" />
        <line class="base-el" x1="575" y1="270" x2="495" y2="225" stroke="#e65100" stroke-width="2" stroke-dasharray="4,4" />
        <line class="side-el" x1="490" y1="90" x2="495" y2="225" stroke="#ea580c" stroke-width="1.5" stroke-dasharray="4,4" />

        
        <polygon class="base-el" points="410,270 575,270 495,225" fill="rgba(255, 152, 0, 0.45)" stroke="#ea580c" stroke-width="2" />

        
        <polygon class="side-el" points="490,90 410,270 495,270" fill="rgba(234, 88, 12, 0.18)" stroke="#ea580c" stroke-width="2" />

        
        <polygon class="side-el" points="490,90 495,270 575,270" fill="rgba(234, 88, 12, 0.28)" stroke="#ea580c" stroke-width="2" />

        
        <line class="side-el" x1="490" y1="90" x2="410" y2="270" stroke="#c2410c" stroke-width="2.5" />
        <line class="side-el" x1="490" y1="90" x2="575" y2="270" stroke="#c2410c" stroke-width="2.5" />
        <line class="base-el" x1="410" y1="270" x2="575" y2="270" stroke="#c2410c" stroke-width="2.5" />

        
        <g id="apex-marker">
          <circle cx="490" cy="90" r="7" fill="#ea580c" />
          <circle cx="490" cy="90" r="13" fill="none" stroke="#ea580c" stroke-width="2" opacity="0.6" />
          <line x1="506" y1="90" x2="528" y2="90" stroke="#ea580c" stroke-width="2" />
          <text x="534" y="95" class="apex-text">Apex (1 Point)</text>
        </g>

        
        <g class="base-el">
          <rect x="445" y="285" width="90" height="22" rx="11" fill="#ffedd5" />
          <text x="490" y="300" font-size="11.5" font-weight="700" fill="#c2410c" text-anchor="middle">1 Base Only ▲</text>
        </g>

        
        <g class="side-el">
          <rect x="555" y="175" width="80" height="22" rx="11" fill="#f8fafc" stroke="#cbd5e1" stroke-width="1" />
          <text x="595" y="190" font-size="11" font-weight="600" fill="#475569" text-anchor="middle">3 Triangles</text>
        </g>
      </g>
    </svg>
  </div>

  <script>
    function setMode(mode) {
      document.querySelectorAll('.btn').forEach(b => b.classList.remove('active'));
      const activeBtn = document.getElementById('btn-' + mode);
      if (activeBtn) activeBtn.classList.add('active');

      const baseEls = document.querySelectorAll('.base-el');
      const sideEls = document.querySelectorAll('.side-el');
      const apexMarker = document.getElementById('apex-marker');

      if (mode === 'all') {
        baseEls.forEach(el => el.classList.remove('dimmed', 'highlighted'));
        sideEls.forEach(el => el.classList.remove('dimmed', 'highlighted'));
        if (apexMarker) apexMarker.classList.remove('dimmed');
      } else if (mode === 'bases') {
        baseEls.forEach(el => { el.classList.remove('dimmed'); el.classList.add('highlighted'); });
        sideEls.forEach(el => { el.classList.add('dimmed'); el.classList.remove('highlighted'); });
        if (apexMarker) apexMarker.classList.add('dimmed');
      } else if (mode === 'sides') {
        baseEls.forEach(el => { el.classList.add('dimmed'); el.classList.remove('highlighted'); });
        sideEls.forEach(el => { el.classList.remove('dimmed'); el.classList.add('highlighted'); });
        if (apexMarker) apexMarker.classList.remove('dimmed');
      }
    }
  </script>
</body>
</html>

Classifying Prisms, Pyramids, Cylinders, Cones, and Spheres

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: transparent;
      color: #1e2945;
      padding: 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }
    .filter-bar {
      display: flex;
      gap: 6px;
      margin-bottom: 12px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .filter-btn {
      appearance: none;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      color: #475569;
      font-size: 13px;
      font-weight: 600;
      padding: 6px 12px;
      border-radius: 20px;
      cursor: pointer;
      transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
    }
    .filter-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
      max-width: 640px;
    }
    .solid-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      transition: box-shadow 0.2s ease, border-color 0.2s ease;
    }
    .solid-title {
      font-size: 15px;
      font-weight: 700;
      color: #0f172a;
      margin-bottom: 6px;
    }
    .svg-container {
      width: 100%;
      max-width: 110px;
      height: 110px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }
    .tags-list {
      display: flex;
      flex-direction: column;
      gap: 5px;
      width: 100%;
      margin-top: 8px;
    }
    .tag {
      font-size: 12px;
      font-weight: 600;
      padding: 4px 6px;
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      transition: opacity 0.2s ease, background-color 0.2s ease;
    }
    .tag-flat {
      background: #dcfce7;
      color: #15803d;
      border: 1px solid #86efac;
    }
    .tag-curved {
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #7dd3fc;
    }
    .tag-point {
      background: #fef3c7;
      color: #b45309;
      border: 1px solid #fcd34d;
    }
    .tag-none {
      background: #f1f5f9;
      color: #64748b;
      border: 1px solid #cbd5e1;
    }
    .highlight-base {
      transition: fill 0.3s ease, stroke 0.3s ease, opacity 0.3s ease;
    }
    .highlight-curved {
      transition: fill 0.3s ease, opacity 0.3s ease;
    }
    .dimmed {
      opacity: 0.25 !important;
    }
    .emphasized {
      filter: drop-shadow(0 0 4px rgba(34, 197, 94, 0.6));
    }
  </style>
</head>
<body>

  <div class="filter-bar">
    <button class="filter-btn active" id="btn-all" onclick="setMode('all')">Show All</button>
    <button class="filter-btn" id="btn-bases" onclick="setMode('bases')">Flat Bases (Green)</button>
    <button class="filter-btn" id="btn-curved" onclick="setMode('curved')">Curved Surfaces</button>
  </div>

  <div class="cards-grid">
    
    <div class="solid-card" id="card-cylinder">
      <div class="solid-title">Cylinder</div>
      <div class="svg-container">
        <svg viewBox="0 0 100 110">
          <defs>
            <linearGradient id="cylBody" x1="0%" y1="0%" x2="100%" y2="0%">
              <stop offset="0%" stop-color="#bae6fd"/>
              <stop offset="40%" stop-color="#e0f2fe"/>
              <stop offset="100%" stop-color="#7dd3fc"/>
            </linearGradient>
            <linearGradient id="greenBase" x1="0%" y1="0%" x2="100%" y2="0%">
              <stop offset="0%" stop-color="#86efac"/>
              <stop offset="100%" stop-color="#4ade80"/>
            </linearGradient>
          </defs>
          
          <ellipse class="highlight-base base-part" cx="50" cy="84" rx="34" ry="12" fill="url(#greenBase)" stroke="#16a34a" stroke-width="2"/>
          
          <path class="highlight-curved curved-part" d="M16 26 v58 a34 12 0 0 0 68 0 v-58 Z" fill="url(#cylBody)" stroke="#0284c7" stroke-width="1.5"/>
          
          <ellipse class="highlight-base base-part" cx="50" cy="26" rx="34" ry="12" fill="url(#greenBase)" stroke="#16a34a" stroke-width="2"/>
        </svg>
      </div>
      <div class="tags-list">
        <div class="tag tag-flat base-part">2 Flat Bases</div>
        <div class="tag tag-curved curved-part">1 Curved Surface</div>
      </div>
    </div>

    
    <div class="solid-card" id="card-cone">
      <div class="solid-title">Cone</div>
      <div class="svg-container">
        <svg viewBox="0 0 100 110">
          <defs>
            <linearGradient id="coneBody" x1="0%" y1="0%" x2="100%" y2="0%">
              <stop offset="0%" stop-color="#bae6fd"/>
              <stop offset="35%" stop-color="#e0f2fe"/>
              <stop offset="100%" stop-color="#7dd3fc"/>
            </linearGradient>
          </defs>
          
          <ellipse class="highlight-base base-part" cx="50" cy="84" rx="36" ry="13" fill="url(#greenBase)" stroke="#16a34a" stroke-width="2"/>
          
          <path class="highlight-curved curved-part" d="M14 84 L50 16 L86 84 a36 13 0 0 1 -72 0 Z" fill="url(#coneBody)" stroke="#0284c7" stroke-width="1.5"/>
          
          <circle class="point-part" cx="50" cy="16" r="3.5" fill="#f59e0b" stroke="#ffffff" stroke-width="1.5"/>
        </svg>
      </div>
      <div class="tags-list">
        <div class="tag tag-flat base-part">1 Flat Base</div>
        <div class="tag tag-curved curved-part">1 Curved Surface</div>
        <div class="tag tag-point point-part">1 Point (Apex)</div>
      </div>
    </div>

    
    <div class="solid-card" id="card-sphere">
      <div class="solid-title">Sphere</div>
      <div class="svg-container">
        <svg viewBox="0 0 100 110">
          <defs>
            <radialGradient id="sphereGrad" cx="35%" cy="35%" r="65%">
              <stop offset="0%" stop-color="#ffffff"/>
              <stop offset="25%" stop-color="#bae6fd"/>
              <stop offset="70%" stop-color="#38bdf8"/>
              <stop offset="100%" stop-color="#0284c7"/>
            </radialGradient>
          </defs>
          
          <circle class="highlight-curved curved-part" cx="50" cy="55" r="38" fill="url(#sphereGrad)" stroke="#0284c7" stroke-width="1.5"/>
          
          <ellipse class="highlight-curved curved-part" cx="50" cy="55" rx="38" ry="11" fill="none" stroke="#ffffff" stroke-width="1.5" stroke-dasharray="3 3" opacity="0.8"/>
        </svg>
      </div>
      <div class="tags-list">
        <div class="tag tag-curved curved-part">All Curved Surface</div>
        <div class="tag tag-none base-part">0 Flat Bases</div>
        <div class="tag tag-none point-part">0 Vertices / Edges</div>
      </div>
    </div>
  </div>

  <script>
    function setMode(mode) {
      document.querySelectorAll('.filter-btn').forEach(b => b.classList.remove('active'));
      document.getElementById('btn-' + mode).classList.add('active');

      const bases = document.querySelectorAll('.base-part');
      const curved = document.querySelectorAll('.curved-part');
      const points = document.querySelectorAll('.point-part');

      if (mode === 'all') {
        bases.forEach(el => { el.classList.remove('dimmed'); el.classList.remove('emphasized'); });
        curved.forEach(el => { el.classList.remove('dimmed'); el.classList.remove('emphasized'); });
        points.forEach(el => { el.classList.remove('dimmed'); el.classList.remove('emphasized'); });
      } else if (mode === 'bases') {
        bases.forEach(el => { el.classList.remove('dimmed'); el.classList.add('emphasized'); });
        curved.forEach(el => { el.classList.add('dimmed'); el.classList.remove('emphasized'); });
        points.forEach(el => { el.classList.add('dimmed'); el.classList.remove('emphasized'); });
      } else if (mode === 'curved') {
        bases.forEach(el => { el.classList.add('dimmed'); el.classList.remove('emphasized'); });
        curved.forEach(el => { el.classList.remove('dimmed'); el.classList.add('emphasized'); });
        points.forEach(el => { el.classList.add('dimmed'); el.classList.remove('emphasized'); });
      }
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 10px 8px;
      user-select: none;
      width: 100%;
    }

    .title {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 8px;
      text-align: center;
    }

    /* Flowchart Container */
    .flowchart {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    /* Decision Nodes */
    .node {
      background: #f8fafc;
      border: 2px solid #cbd5e1;
      border-radius: 12px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      text-align: center;
      transition: all 0.25s ease;
      cursor: pointer;
    }

    .node.root {
      background: #eff6ff;
      border-color: #3b82f6;
      color: #1d4ed8;
      font-size: 14px;
    }

    /* Tree Branching */
    .branches {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
      width: 100%;
    }

    .branch-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    .branch-tag {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      padding: 2px 8px;
      border-radius: 6px;
      letter-spacing: 0.5px;
    }

    .tag-no { background: #fee2e2; color: #b91c1c; }
    .tag-yes { background: #dcfce7; color: #15803d; }

    .sub-branch-grid {
      display: grid;
      width: 100%;
      gap: 6px;
    }
    .grid-2 { grid-template-columns: 1fr 1fr; }
    .grid-3 { grid-template-columns: 1fr 1fr 1fr; }

    /* Shape Cards */
    .shape-card {
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 10px;
      padding: 6px 4px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .shape-card:hover {
      box-shadow: 0 4px 10px rgba(0, 0, 0, 0.08);
      border-color: #94a3b8;
    }

    .shape-card.active {
      border-color: #3b82f6;
      background: #eff6ff;
      box-shadow: 0 0 0 2px #3b82f6;
    }

    .shape-card svg {
      width: 36px;
      height: 36px;
    }

    .shape-label {
      font-size: 11px;
      font-weight: 700;
      color: #334155;
      text-align: center;
      line-height: 1.1;
    }

    .criteria {
      font-size: 9.5px;
      color: #64748b;
      font-weight: 500;
      text-align: center;
      line-height: 1.1;
    }

    /* Path Highlight */
    .highlighted {
      border-color: #3b82f6 !important;
      background: #eff6ff !important;
      color: #1d4ed8 !important;
    }

    /* Prompt helper */
    .hint {
      font-size: 11px;
      color: #64748b;
      margin-top: 4px;
    }
  </style>
</head>
<body>

  <div class="title">Classify Any 3D Shape</div>

  <div class="flowchart">
    
    <div id="node-root" class="node root">
      Curved surface?
    </div>

    
    <div class="branches">
      
      
      <div class="branch-col">
        <span class="branch-tag tag-no">NO → Flat Faces</span>
        
        <div id="node-poly" class="node" style="width: 100%;">
          How many bases?
        </div>

        <div class="sub-branch-grid grid-2">
          
          <div class="shape-card" id="card-prism" onclick="selectShape('prism')">
            <span class="criteria">2 matching<br>bases</span>
            <svg viewBox="0 0 40 40">
              
              <polygon points="8,14 20,6 32,14" fill="#93c5fd" stroke="#2563eb" stroke-width="1.5"/>
              <polygon points="8,14 20,6 20,28 8,36" fill="#bfdbfe" stroke="#2563eb" stroke-width="1.5"/>
              <polygon points="20,6 32,14 32,36 20,28" fill="#60a5fa" stroke="#2563eb" stroke-width="1.5"/>
            </svg>
            <span class="shape-label">Prism</span>
          </div>

          
          <div class="shape-card" id="card-pyramid" onclick="selectShape('pyramid')">
            <span class="criteria">1 base +<br>apex</span>
            <svg viewBox="0 0 40 40">
              
              <polygon points="20,6 6,30 20,36" fill="#bfdbfe" stroke="#2563eb" stroke-width="1.5"/>
              <polygon points="20,6 20,36 34,30" fill="#60a5fa" stroke="#2563eb" stroke-width="1.5"/>
            </svg>
            <span class="shape-label">Pyramid</span>
          </div>
        </div>
      </div>

      
      <div class="branch-col">
        <span class="branch-tag tag-yes">YES → Curved Solids</span>

        <div id="node-curved" class="node" style="width: 100%;">
          Base count?
        </div>

        <div class="sub-branch-grid grid-3">
          
          <div class="shape-card" id="card-cylinder" onclick="selectShape('cylinder')">
            <span class="criteria">2 circles</span>
            <svg viewBox="0 0 40 40">
              <path d="M8,12 C8,8 32,8 32,12 L32,28 C32,32 8,32 8,28 Z" fill="#bbf7d0" stroke="#16a34a" stroke-width="1.5"/>
              <ellipse cx="20" cy="12" rx="12" ry="4" fill="#86efac" stroke="#16a34a" stroke-width="1.5"/>
              <path d="M8,28 C8,32 32,32 32,28" fill="none" stroke="#16a34a" stroke-width="1.5"/>
            </svg>
            <span class="shape-label">Cylinder</span>
          </div>

          
          <div class="shape-card" id="card-cone" onclick="selectShape('cone')">
            <span class="criteria">1 circle</span>
            <svg viewBox="0 0 40 40">
              <polygon points="20,6 8,28 32,28" fill="#bbf7d0" stroke="#16a34a" stroke-width="1.5"/>
              <ellipse cx="20" cy="28" rx="12" ry="4" fill="#86efac" stroke="#16a34a" stroke-width="1.5"/>
            </svg>
            <span class="shape-label">Cone</span>
          </div>

          
          <div class="shape-card" id="card-sphere" onclick="selectShape('sphere')">
            <span class="criteria">0 bases</span>
            <svg viewBox="0 0 40 40">
              <circle cx="20" cy="20" r="14" fill="#86efac" stroke="#16a34a" stroke-width="1.5"/>
              <ellipse cx="20" cy="20" rx="14" ry="4" fill="none" stroke="#16a34a" stroke-width="1.2" stroke-dasharray="2 2"/>
            </svg>
            <span class="shape-label">Sphere</span>
          </div>
        </div>

      </div>

    </div>
  </div>

  <div class="hint">Tap any shape to trace its classification path</div>

  <script>
    const paths = {
      prism: ['node-root', 'node-poly', 'card-prism'],
      pyramid: ['node-root', 'node-poly', 'card-pyramid'],
      cylinder: ['node-root', 'node-curved', 'card-cylinder'],
      cone: ['node-root', 'node-curved', 'card-cone'],
      sphere: ['node-root', 'node-curved', 'card-sphere']
    };

    let currentShape = null;

    function selectShape(type) {
      // Clear previous highlights
      document.querySelectorAll('.node, .shape-card').forEach(el => {
        el.classList.remove('highlighted', 'active');
      });

      if (currentShape === type) {
        currentShape = null;
        return;
      }

      currentShape = type;
      const activeIds = paths[type] || [];
      activeIds.forEach(id => {
        const el = document.getElementById(id);
        if (el) {
          if (el.classList.contains('shape-card')) {
            el.classList.add('active');
          } else {
            el.classList.add('highlighted');
          }
        }
      });
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

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

    .title {
      font-size: 18px;
      font-weight: 700;
      color: #1e2945;
      text-align: center;
      margin-bottom: 12px;
    }

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

    .family-card {
      border: 1px solid #e6e6e6;
      border-radius: 12px;
      padding: 12px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .polyhedra-card {
      background: #f0f7ff;
    }

    .curved-card {
      background: #fff7ed;
    }

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

    .family-name {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }

    .family-desc {
      font-size: 12px;
      font-weight: 500;
      color: #475569;
      margin-top: 2px;
    }

    .shapes-row {
      display: flex;
      flex-direction: row;
      justify-content: space-around;
      align-items: flex-end;
      width: 100%;
      gap: 6px;
    }

    .shape-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      flex: 1;
      cursor: pointer;
      border-radius: 8px;
      padding: 4px 2px;
      transition: background-color 0.2s ease;
    }

    .shape-item:hover {
      background-color: rgba(30, 41, 69, 0.05);
    }

    .shape-svg {
      width: 100%;
      max-width: 64px;
      height: 60px;
    }

    .shape-label {
      font-size: 12px;
      font-weight: 600;
      color: #1e2945;
      margin-top: 6px;
      text-align: center;
      line-height: 1.1;
    }

    @media (max-width: 440px) {
      .title {
        font-size: 16px;
        margin-bottom: 8px;
      }
      .family-card {
        padding: 8px 6px;
      }
      .family-name {
        font-size: 13px;
      }
      .family-desc {
        font-size: 11px;
      }
      .shape-svg {
        max-width: 48px;
        height: 48px;
      }
      .shape-label {
        font-size: 11px;
      }
    }
  </style>
</head>
<body>

  <h1 class="title">3D Shape Families</h1>

  <div class="families-grid">
    
    <div class="family-card polyhedra-card">
      <div class="family-header">
        <div class="family-name">Polyhedra</div>
        <div class="family-desc">Flat Faces Only</div>
      </div>

      <div class="shapes-row">
        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            
            <polygon points="30,8 52,19 30,30 8,19" fill="#93c5fd" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="8,19 30,30 30,52 8,41" fill="#3b82f6" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="30,30 52,19 52,41 30,52" fill="#1d4ed8" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
          </svg>
          <span class="shape-label">Cube</span>
        </div>

        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            
            <polygon points="30,12 54,20 30,28 6,20" fill="#93c5fd" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="6,20 30,28 30,48 6,40" fill="#3b82f6" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="30,28 54,20 54,40 30,48" fill="#1d4ed8" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
          </svg>
          <span class="shape-label">Box</span>
        </div>

        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            
            <polygon points="30,8 10,46 32,50" fill="#3b82f6" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="30,8 32,50 50,42" fill="#1d4ed8" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
            
            <polygon points="10,46 32,50 50,42" fill="#2563eb" stroke="#1d4ed8" stroke-width="1.5" stroke-linejoin="round"/>
          </svg>
          <span class="shape-label">Pyramid</span>
        </div>
      </div>
    </div>

    
    <div class="family-card curved-card">
      <div class="family-header">
        <div class="family-name">Curved Solids</div>
        <div class="family-desc">Rounded Surfaces</div>
      </div>

      <div class="shapes-row">
        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            <defs>
              <linearGradient id="cylGrad" x1="0%" y1="0%" x2="100%" y2="0%">
                <stop offset="0%" stop-color="#ea580c"/>
                <stop offset="35%" stop-color="#fdba74"/>
                <stop offset="70%" stop-color="#fb923c"/>
                <stop offset="100%" stop-color="#9a3412"/>
              </linearGradient>
            </defs>
            
            <path d="M14,18 L14,42 A16,6 0 0,0 46,42 L46,18 Z" fill="url(#cylGrad)" stroke="#9a3412" stroke-width="1.5"/>
            
            <ellipse cx="30" cy="18" rx="16" ry="6" fill="#fed7aa" stroke="#9a3412" stroke-width="1.5"/>
          </svg>
          <span class="shape-label">Cylinder</span>
        </div>

        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            <defs>
              <linearGradient id="coneGrad" x1="0%" y1="0%" x2="100%" y2="0%">
                <stop offset="0%" stop-color="#ea580c"/>
                <stop offset="35%" stop-color="#fdba74"/>
                <stop offset="80%" stop-color="#c2410c"/>
                <stop offset="100%" stop-color="#9a3412"/>
              </linearGradient>
            </defs>
            
            <path d="M30,8 L13,44 A17,6 0 0,0 47,44 Z" fill="url(#coneGrad)" stroke="#9a3412" stroke-width="1.5" stroke-linejoin="round"/>
          </svg>
          <span class="shape-label">Cone</span>
        </div>

        
        <div class="shape-item">
          <svg class="shape-svg" viewBox="0 0 60 60">
            <defs>
              <radialGradient id="sphereGrad" cx="35%" cy="35%" r="65%">
                <stop offset="0%" stop-color="#ffedd5"/>
                <stop offset="25%" stop-color="#fb923c"/>
                <stop offset="75%" stop-color="#ea580c"/>
                <stop offset="100%" stop-color="#7c2d12"/>
              </radialGradient>
            </defs>
            <circle cx="30" cy="30" r="20" fill="url(#sphereGrad)" stroke="#9a3412" stroke-width="1.5"/>
          </svg>
          <span class="shape-label">Sphere</span>
        </div>
      </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">
  <meta name="aspect-ratio" content="4:3">
  <title>Prism Anatomy</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      min-height: 100%;
      padding: 12px 16px;
      user-select: none;
    }

    .badges {
      display: flex;
      gap: 8px;
      justify-content: center;
      width: 100%;
      max-width: 480px;
      margin-bottom: 4px;
    }

    .badge {
      flex: 1;
      text-align: center;
      padding: 6px 8px;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      border: 1.5px solid transparent;
      transition: all 0.2s ease;
    }

    .badge-face { background: #e0f2fe; color: #0369a1; border-color: #bae6fd; }
    .badge-edge { background: #f1f5f9; color: #334155; border-color: #cbd5e1; }
    .badge-vertex { background: #fef9c3; color: #854d0e; border-color: #fde047; }

    .badge.active {
      box-shadow: 0 0 0 2px #1e2945;
    }

    .svg-container {
      width: 100%;
      max-width: 520px;
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    .callout-box {
      filter: drop-shadow(0 2px 4px rgba(0,0,0,0.06));
    }

    .label-title {
      font-size: 13px;
      font-weight: 700;
    }

    .label-sub {
      font-size: 11px;
      font-weight: 500;
      fill: #64748b;
    }

    .interactive-part {
      cursor: pointer;
      transition: opacity 0.2s ease;
    }
  </style>
</head>
<body>

  
  <div class="badges">
    <div class="badge badge-face active" id="btn-face" onclick="highlight('face')">6 Faces</div>
    <div class="badge badge-edge" id="btn-edge" onclick="highlight('edge')">12 Edges</div>
    <div class="badge badge-vertex" id="btn-vertex" onclick="highlight('vertex')">8 Vertices</div>
  </div>

  
  <div class="svg-container">
    <svg viewBox="0 0 520 340">
      <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="#475569" />
        </marker>
        <marker id="arrow-blue" 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="#0284c7" />
        </marker>
        <marker id="arrow-gold" 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="#ca8a04" />
        </marker>
      </defs>

      
      <g id="hidden-edges" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="4,4" fill="none">
        <line x1="260" y1="180" x2="160" y2="230" />
        <line x1="260" y1="180" x2="360" y2="230" />
        <line x1="260" y1="180" x2="260" y2="70" />
      </g>

      
      <g id="faces">
        
        <polygon id="face-top" class="interactive-part" points="260,70 360,120 260,170 160,120"
          fill="#f8fafc" stroke="#64748b" stroke-width="1.5" />

        
        <polygon id="face-right" class="interactive-part" points="260,170 360,120 360,230 260,280"
          fill="#f1f5f9" stroke="#64748b" stroke-width="1.5" />

        
        <polygon id="face-left" class="interactive-part" points="160,120 260,170 260,280 160,230"
          fill="#bae6fd" stroke="#0284c7" stroke-width="2" />
      </g>

      
      <line id="edge-highlight" x1="260" y1="170" x2="360" y2="120"
        stroke="#0f172a" stroke-width="4" stroke-linecap="round" />

      
      <g id="all-edges" stroke="#334155" stroke-width="2" stroke-linecap="round" fill="none">
        
        <line x1="260" y1="70" x2="160" y2="120" />
        <line x1="260" y1="70" x2="360" y2="120" />
        <line x1="160" y1="120" x2="160" y2="230" />
        <line x1="360" y1="120" x2="360" y2="230" />
        <line x1="160" y1="230" x2="260" y2="280" />
        <line x1="360" y1="230" x2="260" y2="280" />
        <line x1="160" y1="120" x2="260" y2="170" />
        <line x1="260" y1="170" x2="260" y2="280" />
      </g>

      
      <g id="all-vertices">
        <circle cx="260" cy="70" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="160" cy="120" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="360" cy="120" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="160" cy="230" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="360" cy="230" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="260" cy="280" r="4.5" fill="#e2e8f0" stroke="#64748b" stroke-width="1.5" />
        <circle cx="260" cy="180" r="4" fill="#cbd5e1" stroke="#94a3b8" stroke-dasharray="2,2" stroke-width="1" />
      </g>

      
      <g id="vertex-highlight">
        <circle cx="260" cy="170" r="11" fill="#fde047" opacity="0.4" />
        <circle cx="260" cy="170" r="6" fill="#eab308" stroke="#ffffff" stroke-width="2" />
      </g>

      

      
      <g id="callout-face">
        <path d="M 95 195 L 180 195" fill="none" stroke="#0284c7" stroke-width="1.5" marker-end="url(#arrow-blue)" />
        <g transform="translate(8, 168)">
          <rect width="118" height="42" rx="6" fill="#ffffff" stroke="#bae6fd" stroke-width="1.5" />
          <text x="59" y="17" text-anchor="middle" class="label-title" fill="#0369a1">Face</text>
          <text x="59" y="32" text-anchor="middle" class="label-sub">Flat polygon</text>
        </g>
      </g>

      
      <g id="callout-vertex">
        <path d="M 195 90 Q 220 120 252 162" fill="none" stroke="#ca8a04" stroke-width="1.5" marker-end="url(#arrow-gold)" />
        <g transform="translate(70, 48)">
          <rect width="128" height="42" rx="6" fill="#ffffff" stroke="#fde047" stroke-width="1.5" />
          <text x="64" y="17" text-anchor="middle" class="label-title" fill="#a16207">Vertex</text>
          <text x="64" y="32" text-anchor="middle" class="label-sub">Corner point</text>
        </g>
      </g>

      
      <g id="callout-edge">
        <path d="M 400 95 L 320 135" fill="none" stroke="#475569" stroke-width="1.5" marker-end="url(#arrow)" />
        <g transform="translate(372, 68)">
          <rect width="140" height="42" rx="6" fill="#ffffff" stroke="#cbd5e1" stroke-width="1.5" />
          <text x="70" y="17" text-anchor="middle" class="label-title" fill="#1e2945">Edge</text>
          <text x="70" y="32" text-anchor="middle" class="label-sub">Where 2 faces meet</text>
        </g>
      </g>

    </svg>
  </div>

  <script>
    function highlight(type) {
      document.getElementById('btn-face').classList.toggle('active', type === 'face');
      document.getElementById('btn-edge').classList.toggle('active', type === 'edge');
      document.getElementById('btn-vertex').classList.toggle('active', type === 'vertex');

      const faceLeft = document.getElementById('face-left');
      const faceTop = document.getElementById('face-top');
      const faceRight = document.getElementById('face-right');
      const edgeHigh = document.getElementById('edge-highlight');
      const vertexHigh = document.getElementById('vertex-highlight');
      const allVertices = document.getElementById('all-vertices');

      if (type === 'face') {
        faceLeft.setAttribute('fill', '#bae6fd');
        faceTop.setAttribute('fill', '#e0f2fe');
        faceRight.setAttribute('fill', '#e0f2fe');
        edgeHigh.setAttribute('stroke', '#64748b');
        edgeHigh.setAttribute('stroke-width', '2');
        vertexHigh.style.opacity = '0.5';
        allVertices.style.opacity = '0.3';
      } else if (type === 'edge') {
        faceLeft.setAttribute('fill', '#f8fafc');
        faceTop.setAttribute('fill', '#f8fafc');
        faceRight.setAttribute('fill', '#f8fafc');
        edgeHigh.setAttribute('stroke', '#0f172a');
        edgeHigh.setAttribute('stroke-width', '4.5');
        vertexHigh.style.opacity = '0.3';
        allVertices.style.opacity = '0.3';
      } else if (type === 'vertex') {
        faceLeft.setAttribute('fill', '#f8fafc');
        faceTop.setAttribute('fill', '#f8fafc');
        faceRight.setAttribute('fill', '#f8fafc');
        edgeHigh.setAttribute('stroke', '#64748b');
        edgeHigh.setAttribute('stroke-width', '1.5');
        vertexHigh.style.opacity = '1';
        allVertices.style.opacity = '1';
        Array.from(allVertices.children).forEach(dot => {
          dot.setAttribute('fill', '#fde047');
          dot.setAttribute('stroke', '#ca8a04');
        });
      }
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 12px;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      width: 100%;
      max-width: 640px;
    }
    @media (max-width: 480px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }
    .tri-card {
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 14px;
      padding: 12px 8px 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      cursor: pointer;
      transition: border-color 0.25s ease, box-shadow 0.25s ease;
      position: relative;
    }
    .tri-card:hover, .tri-card.active {
      border-color: #22b7ff;
      box-shadow: 0 4px 16px rgba(34, 183, 255, 0.18);
    }
    .title {
      font-size: 15px;
      font-weight: 800;
      color: #0f172a;
      margin-bottom: 2px;
      text-align: center;
    }
    .subtitle {
      font-size: 12px;
      font-weight: 600;
      color: #64748b;
      margin-bottom: 6px;
      text-align: center;
    }
    .svg-wrap {
      width: 100%;
      max-width: 170px;
      aspect-ratio: 16 / 13;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }
    .shape-acute {
      fill: rgba(34, 183, 255, 0.12);
      stroke: #0284c7;
      stroke-width: 2.5;
      stroke-linejoin: round;
    }
    .shape-right {
      fill: rgba(16, 185, 129, 0.12);
      stroke: #059669;
      stroke-width: 2.5;
      stroke-linejoin: round;
    }
    .shape-obtuse {
      fill: rgba(245, 158, 11, 0.12);
      stroke: #d97706;
      stroke-width: 2.5;
      stroke-linejoin: round;
    }
    .arc {
      fill: none;
      stroke-width: 1.5;
    }
    .arc-normal {
      stroke: #94a3b8;
    }
    .arc-focus {
      stroke-width: 2.5;
    }
    .badge {
      font-size: 11px;
      font-weight: 800;
      padding: 3px 8px;
      border-radius: 20px;
      display: inline-flex;
      align-items: center;
      gap: 3px;
      margin-top: 4px;
      letter-spacing: 0.2px;
    }
    .badge-acute {
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #bae6fd;
      box-shadow: 0 0 8px rgba(34, 183, 255, 0.4);
    }
    .badge-right {
      background: #d1fae5;
      color: #047857;
      border: 1px solid #a7f3d0;
      box-shadow: 0 0 8px rgba(16, 185, 129, 0.4);
    }
    .badge-obtuse {
      background: #fef3c7;
      color: #b45309;
      border: 1px solid #fde68a;
      box-shadow: 0 0 8px rgba(245, 158, 11, 0.4);
    }
    .angle-text {
      font-size: 11px;
      font-weight: 700;
      fill: #475569;
      font-family: inherit;
    }
    .angle-focus-text {
      font-size: 12px;
      font-weight: 800;
      font-family: inherit;
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="tri-card active" onclick="selectCard(this)">
      <div class="title">Acute</div>
      <div class="subtitle">All &lt; 90°</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 160 130">
          
          <polygon points="70,32 135,115 25,115" class="shape-acute" />
          
          
          <path d="M 43,115 A 18 18 0 0 0 34,99" class="arc arc-normal" />
          <text x="44" y="108" class="angle-text">60°</text>
          
          
          <path d="M 118,115 A 18 18 0 0 1 124,103" class="arc arc-normal" />
          <text x="100" y="108" class="angle-text">50°</text>

          
          <circle cx="70" cy="32" r="14" fill="#0284c7" fill-opacity="0.15" />
          <path d="M 61,50 A 20 20 0 0 0 81,46" class="arc arc-focus" stroke="#0284c7" />
          <text x="70" y="22" text-anchor="middle" class="angle-focus-text" fill="#0369a1">70°</text>
        </svg>
      </div>
      <div class="badge badge-acute">✦ Max: 70°</div>
    </div>

    
    <div class="tri-card" onclick="selectCard(this)">
      <div class="title">Right</div>
      <div class="subtitle">One = 90°</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 160 130">
          
          <polygon points="30,54 135,115 30,115" class="shape-right" />
          
          
          <path d="M 112,115 A 24 24 0 0 1 116,104" class="arc arc-normal" />
          <text x="96" y="108" class="angle-text">30°</text>
          
          
          <path d="M 30,76 A 22 22 0 0 0 49,65" class="arc arc-normal" />
          <text x="40" y="80" class="angle-text">60°</text>

          
          <rect x="30" y="99" width="16" height="16" fill="#059669" fill-opacity="0.2" stroke="#059669" stroke-width="2" />
          <text x="56" y="108" class="angle-focus-text" fill="#047857">90°</text>
        </svg>
      </div>
      <div class="badge badge-right">✦ Square: 90°</div>
    </div>

    
    <div class="tri-card" onclick="selectCard(this)">
      <div class="title">Obtuse</div>
      <div class="subtitle">One &gt; 90°</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 160 130">
          
          <polygon points="25,53 145,105 55,105" class="shape-obtuse" />
          
          
          <path d="M 38,76 A 26 26 0 0 0 50,64" class="arc arc-normal" />
          <text x="42" y="70" class="angle-text">35°</text>
          
          
          <path d="M 121,105 A 24 24 0 0 1 126,97" class="arc arc-normal" />
          <text x="105" y="100" class="angle-text">25°</text>

          
          <circle cx="55" cy="105" r="16" fill="#d97706" fill-opacity="0.18" />
          <path d="M 73,105 A 18 18 0 0 0 46,89" class="arc arc-focus" stroke="#d97706" />
          <text x="66" y="90" class="angle-focus-text" fill="#b45309">120°</text>
        </svg>
      </div>
      <div class="badge badge-obtuse">✦ Max: 120°</div>
    </div>
  </div>

  <script>
    function selectCard(card) {
      document.querySelectorAll('.tri-card').forEach(c => c.classList.remove('active'));
      card.classList.add('active');
    }
  </script>
</body>
</html>

Classifying Triangles by Angles: Acute, Right, Obtuse

<!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>Acute Triangle Tester</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100vh;
      padding: 12px;
      user-select: none;
    }

    .toolbar {
      display: flex;
      gap: 6px;
      flex-wrap: wrap;
      justify-content: center;
      width: 100%;
      max-width: 480px;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
      transition: background 0.2s, color 0.2s, border-color 0.2s;
    }

    .btn:active {
      background: #e2e8f0;
    }

    .btn.active {
      background: #ecfdf5;
      border-color: #10b981;
      color: #047857;
      box-shadow: 0 0 0 1px #10b981;
    }

    .stage-container {
      position: relative;
      width: 100%;
      max-width: 420px;
      height: 250px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    .checklist-card {
      width: 100%;
      max-width: 480px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 14px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

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

    .check-item {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 6px 8px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      display: flex;
      align-items: center;
      justify-content: space-between;
      transition: all 0.25s ease;
    }

    .check-item.active {
      border-color: #10b981;
      background: #ecfdf5;
      color: #065f46;
      box-shadow: 0 1px 3px rgba(16, 185, 129, 0.15);
    }

    .check-item .badge {
      font-size: 12px;
      color: #94a3b8;
    }

    .check-item.active .badge {
      color: #10b981;
      font-weight: 700;
    }

    .result-badge {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      background: #f1f5f9;
      color: #475569;
      font-size: 13px;
      font-weight: 700;
      padding: 6px 12px;
      border-radius: 6px;
      border: 1px dashed #cbd5e1;
      transition: all 0.25s ease;
    }

    .result-badge.complete {
      background: #10b981;
      color: #ffffff;
      border: 1px solid #059669;
      box-shadow: 0 2px 6px rgba(16, 185, 129, 0.3);
    }

    /* Interactive clickable triangle corners */
    .corner-hit {
      cursor: pointer;
      fill: transparent;
    }
  </style>
</head>
<body>

  
  <div class="toolbar">
    <button class="btn active" id="btn-0" onclick="selectStep(0)">∠ 65°</button>
    <button class="btn" id="btn-1" onclick="selectStep(1)">∠ 60°</button>
    <button class="btn" id="btn-2" onclick="selectStep(2)">∠ 55°</button>
    <button class="btn" id="btn-all" onclick="selectStep(3)">All 3 ✓</button>
  </div>

  
  <div class="stage-container">
    <svg viewBox="0 0 380 250" id="mainSvg">
      
      <polygon id="triPoly" points="75,220 167,28 305,220"
        fill="#f0fdf4" stroke="#10b981" stroke-width="3.5" stroke-linejoin="round" />

      
      
      <path id="arc-b" d="M 115 220 A 40 40 0 0 0 91.9 183.7" fill="none" stroke="#10b981" stroke-width="2.5" />
      
      
      <path id="arc-a" d="M 150.1 64.3 A 40 40 0 0 0 190.4 60.5" fill="none" stroke="#10b981" stroke-width="2.5" />

      
      <path id="arc-c" d="M 282.1 187.2 A 40 40 0 0 0 265 220" fill="none" stroke="#10b981" stroke-width="2.5" />

      
      <text x="110" y="206" font-size="14" font-weight="700" fill="#047857">65°</text>
      <text x="167" y="80" text-anchor="middle" font-size="14" font-weight="700" fill="#047857">60°</text>
      <text x="268" y="206" text-anchor="end" font-size="14" font-weight="700" fill="#047857">55°</text>

      
      <g id="tester" style="transition: transform 0.45s cubic-bezier(0.2, 0.9, 0.3, 1), opacity 0.3s ease;">
        
        <path d="M 0 0 L 70 0 L 70 -70 L 0 -70 Z" fill="rgba(239, 68, 68, 0.12)" stroke="#ef4444" stroke-width="2" stroke-dasharray="4 2" />
        
        <path d="M 0 -18 L 18 -18 L 18 0" fill="none" stroke="#ef4444" stroke-width="2" />
        
        <text x="24" y="-30" font-size="11" font-weight="700" fill="#dc2626">90°</text>
      </g>

      
      <circle class="corner-hit" cx="75" cy="220" r="38" onclick="selectStep(0)" />
      <circle class="corner-hit" cx="167" cy="28" r="38" onclick="selectStep(1)" />
      <circle class="corner-hit" cx="305" cy="220" r="38" onclick="selectStep(2)" />
    </svg>
  </div>

  
  <div class="checklist-card">
    <div class="checklist-row">
      <div class="check-item" id="item-0">
        <span>65° &lt; 90°</span>
        <span class="badge" id="badge-0">✓</span>
      </div>
      <div class="check-item" id="item-1">
        <span>60° &lt; 90°</span>
        <span class="badge" id="badge-1">✓</span>
      </div>
      <div class="check-item" id="item-2">
        <span>55° &lt; 90°</span>
        <span class="badge" id="badge-2">✓</span>
      </div>
    </div>
    <div class="result-badge" id="resultCard">
      <span>Result: Acute Triangle (All &lt; 90°)</span>
    </div>
  </div>

  <script>
    // Exact tester transformations for each corner:
    // Corner B (75, 220): Base line goes right (0 deg), 90 deg goes up (-90 deg). Angle 65° is inside the 90° square.
    // Corner A (167, 28): Aligned along side AC (angle ~54.3°), right angle extends 90° counter-clockwise.
    // Corner C (305, 220): Base line goes left (180 deg), 90 deg goes up (-90 deg). Angle 55° is inside the 90° square.
    const steps = [
      { transform: "translate(75px, 220px) rotate(0deg)", item: 0 },
      { transform: "translate(167px, 28px) rotate(54.3deg)", item: 1 },
      { transform: "translate(305px, 220px) scale(-1, 1) rotate(0deg)", item: 2 }
    ];

    let currentStep = 0;
    let autoTimer = null;

    function applyState(index) {
      // Update buttons
      for (let i = 0; i < 3; i++) {
        document.getElementById('btn-' + i).classList.toggle('active', index === i);
      }
      document.getElementById('btn-all').classList.toggle('active', index === 3);

      const tester = document.getElementById('tester');
      const resultCard = document.getElementById('resultCard');

      if (index < 3) {
        tester.style.opacity = '1';
        tester.style.transform = steps[index].transform;

        // Highlight checklist item
        for (let i = 0; i < 3; i++) {
          document.getElementById('item-' + i).classList.toggle('active', i === index);
        }
        resultCard.classList.remove('complete');
      } else {
        // All complete state
        tester.style.opacity = '0';
        for (let i = 0; i < 3; i++) {
          document.getElementById('item-' + i).classList.add('active');
        }
        resultCard.classList.add('complete');
      }
    }

    function selectStep(idx) {
      clearInterval(autoTimer);
      currentStep = idx;
      applyState(currentStep);
    }

    // Auto cycle through steps smoothly
    function startCycle() {
      autoTimer = setInterval(() => {
        currentStep = (currentStep + 1) % 4;
        applyState(currentStep);
      }, 3200);
    }

    applyState(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>Right Triangle Angles</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }
    body {
      width: 100%;
      min-height: 100vh;
      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: center;
      padding: 12px;
    }
    .diagram-wrap {
      width: 100%;
      max-width: 460px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 12px;
    }
    .nav-tabs {
      display: flex;
      gap: 8px;
      width: 100%;
      justify-content: center;
    }
    .tab-btn {
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 6px;
      padding: 6px 12px;
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      transition: background-color 0.2s, border-color 0.2s, color 0.2s;
    }
    .tab-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }
    .tab-btn.active {
      background: #1e293b;
      border-color: #1e293b;
      color: #ffffff;
    }
    svg {
      width: 100%;
      height: auto;
      overflow: visible;
    }
    .triangle-poly {
      fill: #ffffff;
      stroke: #334155;
      stroke-width: 3;
      stroke-linejoin: round;
      filter: drop-shadow(0 2px 5px rgba(0, 0, 0, 0.05));
    }
    .angle-arc {
      fill: rgba(245, 158, 11, 0.12);
      stroke: #d97706;
      stroke-width: 2.5;
      stroke-linecap: round;
      transition: fill 0.25s ease, stroke-width 0.25s ease;
    }
    .right-box {
      fill: rgba(37, 99, 235, 0.12);
      stroke: #2563eb;
      stroke-width: 2.5;
      stroke-linecap: square;
      stroke-linejoin: miter;
      transition: fill 0.25s ease, stroke-width 0.25s ease;
    }
    .interactive-group {
      cursor: pointer;
      transition: opacity 0.25s ease;
    }
    .interactive-group:hover .right-box {
      fill: rgba(37, 99, 235, 0.25);
    }
    .interactive-group:hover .angle-arc {
      fill: rgba(245, 158, 11, 0.25);
    }
    .lbl-val {
      font-size: 15px;
      font-weight: 700;
    }
    .lbl-type {
      font-size: 11px;
      font-weight: 600;
      letter-spacing: 0.3px;
    }
    .lbl-right { fill: #2563eb; }
    .lbl-acute { fill: #d97706; }

    .badge-bar {
      width: 100%;
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      text-align: center;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    }
    .badge-text {
      font-size: 13px;
      font-weight: 600;
      color: #1e293b;
      line-height: 1.4;
    }
    .b-blue {
      color: #2563eb;
      font-weight: 700;
    }
    .b-amber {
      color: #d97706;
      font-weight: 700;
    }
  </style>
</head>
<body>

  <div class="diagram-wrap">
    <div class="nav-tabs">
      <button class="tab-btn active" onclick="setMode('all')">Show All</button>
      <button class="tab-btn" onclick="setMode('right')">90° Right Angle</button>
      <button class="tab-btn" onclick="setMode('acute')">Acute Angles</button>
    </div>

    <svg viewBox="0 0 440 280">
      
      <polygon points="80,240 360,240 80,30" class="triangle-poly" />

      
      <g id="grp-right" class="interactive-group" onclick="setMode('right')">
        <path d="M 80,208 L 112,208 L 112,240" class="right-box" />
        <text x="122" y="206" class="lbl-val lbl-right">90°</text>
        <text x="122" y="222" class="lbl-type lbl-right">Right</text>
      </g>

      
      <g id="grp-acute1" class="interactive-group" onclick="setMode('acute')">
        
        <path d="M 80,75 A 45,45 0 0,0 114.5,58.9" class="angle-arc" />
        <text x="96" y="88" class="lbl-val lbl-acute">50°</text>
        <text x="96" y="103" class="lbl-type lbl-acute">Acute</text>
      </g>

      
      <g id="grp-acute2" class="interactive-group" onclick="setMode('acute')">
        
        <path d="M 308,240 A 52,52 0 0,1 320.2,206.6" class="angle-arc" />
        <text x="272" y="206" class="lbl-val lbl-acute" text-anchor="middle">40°</text>
        <text x="272" y="222" class="lbl-type lbl-acute" text-anchor="middle">Acute</text>
      </g>
    </svg>

    <div class="badge-bar">
      <div class="badge-text" id="status-badge">
        <span class="b-blue">1 Right Angle (90°)</span> + <span class="b-amber">2 Acute Angles (50°, 40°)</span> = <strong>Right Triangle</strong>
      </div>
    </div>
  </div>

  <script>
    function setMode(mode) {
      const gRight = document.getElementById('grp-right');
      const gA1 = document.getElementById('grp-acute1');
      const gA2 = document.getElementById('grp-acute2');
      const btns = document.querySelectorAll('.tab-btn');

      btns[0].classList.toggle('active', mode === 'all');
      btns[1].classList.toggle('active', mode === 'right');
      btns[2].classList.toggle('active', mode === 'acute');

      if (mode === 'right') {
        gRight.style.opacity = '1';
        gA1.style.opacity = '0.22';
        gA2.style.opacity = '0.22';
      } else if (mode === 'acute') {
        gRight.style.opacity = '0.22';
        gA1.style.opacity = '1';
        gA2.style.opacity = '1';
      } else {
        gRight.style.opacity = '1';
        gA1.style.opacity = '1';
        gA2.style.opacity = '1';
      }
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 16px 16px;
      user-select: none;
    }

    .diagram-stage {
      width: 100%;
      max-width: 500px;
      position: relative;
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    .triangle-poly {
      fill: #f8fafc;
      stroke: #334155;
      stroke-width: 3;
      stroke-linejoin: round;
    }

    /* Arcs & Sectors */
    .arc-obtuse-bg {
      fill: #ffe4e6;
      opacity: 0.7;
    }
    .arc-obtuse {
      fill: none;
      stroke: #f43f5e;
      stroke-width: 3.5;
      stroke-linecap: round;
    }

    .arc-acute-bg {
      fill: #e0f2fe;
      opacity: 0.7;
    }
    .arc-acute {
      fill: none;
      stroke: #0284c7;
      stroke-width: 2.5;
      stroke-linecap: round;
    }

    .ref-line {
      stroke: #94a3b8;
      stroke-dasharray: 4 3;
      stroke-width: 1.5;
    }

    /* Badges & Labels */
    .label-val {
      font-size: 16px;
      font-weight: 700;
      text-anchor: middle;
      dominant-baseline: central;
    }
    .label-val.obtuse { fill: #e11d48; }
    .label-val.acute { fill: #0369a1; }

    .tag-text {
      font-size: 12px;
      font-weight: 600;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .formula-card {
      width: 100%;
      max-width: 480px;
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px 8px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
    }

    .pill {
      display: inline-flex;
      align-items: center;
      padding: 3px 8px;
      border-radius: 6px;
      font-weight: 700;
      font-size: 12px;
      line-height: 1.2;
    }
    .pill-obtuse {
      background: #ffe4e6;
      color: #e11d48;
      border: 1px solid #fecdd3;
    }
    .pill-acute {
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #bae6fd;
    }
    .pill-result {
      background: #ede9fe;
      color: #6d28d9;
      border: 1px solid #ddd6fe;
    }
    .op {
      font-weight: 800;
      color: #94a3b8;
      font-size: 14px;
    }
  </style>
</head>
<body>

  <div class="diagram-stage">
    <svg viewBox="20 20 440 240" aria-label="Obtuse Triangle with angles 115°, 35°, and 30°">
      
      
      <polygon class="triangle-poly" points="60,210 205,100 415,210" />

      
      
      <path class="arc-obtuse-bg" d="M 205 100 L 236 116.3 A 35 35 0 0 1 177.1 121.2 Z" />
      <path class="arc-obtuse" d="M 236 116.3 A 35 35 0 0 1 177.1 121.2" />

      
      <line class="ref-line" x1="205" y1="100" x2="160" y2="40" />
      <path class="ref-line" d="M 194.5 86.2 L 207 76.5 L 217.5 90.2" fill="none" />

      
      
      <path class="arc-acute-bg" d="M 60 210 L 105 210 A 45 45 0 0 0 96.9 184.2 Z" />
      <path class="arc-acute" d="M 105 210 A 45 45 0 0 0 96.9 184.2" />

      
      
      <path class="arc-acute-bg" d="M 415 210 L 368 210 A 47 47 0 0 1 373.3 186.5 Z" />
      <path class="arc-acute" d="M 368 210 A 47 47 0 0 1 373.3 186.5" />

      
      
      <g transform="translate(205, 42)">
        <rect x="-56" y="-13" width="112" height="26" rx="13" fill="#fff1f2" stroke="#f43f5e" stroke-width="1.5" />
        <text class="tag-text" y="1" fill="#e11d48">Obtuse (&gt;90°)</text>
      </g>
      <text class="label-val obtuse" x="205" y="132">115°</text>

      
      <text class="label-val acute" x="122" y="196">35°</text>
      <g transform="translate(60, 236)">
        <rect x="-24" y="-10" width="48" height="20" rx="5" fill="#f0f9ff" stroke="#bae6fd" stroke-width="1" />
        <text class="tag-text" y="1" fill="#0369a1">Acute</text>
      </g>

      
      <text class="label-val acute" x="348" y="198">30°</text>
      <g transform="translate(415, 236)">
        <rect x="-24" y="-10" width="48" height="20" rx="5" fill="#f0f9ff" stroke="#bae6fd" stroke-width="1" />
        <text class="tag-text" y="1" fill="#0369a1">Acute</text>
      </g>
    </svg>
  </div>

  
  <div class="formula-card">
    <span class="pill pill-obtuse">1 Obtuse Angle</span>
    <span class="op">+</span>
    <span class="pill pill-acute">2 Acute Angles</span>
    <span class="op">=</span>
    <span class="pill pill-result">Obtuse Triangle</span>
  </div>

</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%;
      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;
      padding: 10px;
      gap: 10px;
      user-select: none;
    }

    .controls {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      justify-content: center;
      width: 100%;
      max-width: 480px;
    }

    .btn {
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 13px;
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      transition: background-color 0.2s, border-color 0.2s, color 0.2s;
    }
    .btn:hover {
      border-color: #94a3b8;
    }
    .btn.active {
      background: #2563eb;
      border-color: #2563eb;
      color: #ffffff;
    }

    .canvas-box {
      width: 100%;
      max-width: 480px;
      height: 250px;
      position: relative;
    }

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

    .banner {
      position: absolute;
      top: 8px;
      left: 50%;
      transform: translateX(-50%);
      background: #fef2f2;
      border: 1.5px solid #f87171;
      color: #b91c1c;
      padding: 5px 14px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 700;
      display: flex;
      align-items: center;
      gap: 6px;
      white-space: nowrap;
      transition: background-color 0.25s, border-color 0.25s, color 0.25s;
      box-shadow: 0 2px 5px rgba(0,0,0,0.06);
      z-index: 10;
    }
    .banner.valid {
      background: #f0fdf4;
      border-color: #4ade80;
      color: #15803d;
    }
    .banner.parallel {
      background: #fffbeb;
      border-color: #fcd34d;
      color: #b45309;
    }

    .slider-row {
      display: flex;
      align-items: center;
      gap: 12px;
      width: 100%;
      max-width: 480px;
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      padding: 0 4px;
      flex-wrap: wrap;
      justify-content: space-between;
    }
    .slider-group {
      display: flex;
      align-items: center;
      gap: 8px;
      flex: 1;
      min-width: 180px;
    }
    .slider-group input {
      flex: 1;
      accent-color: #2563eb;
      cursor: pointer;
    }
  </style>
</head>
<body>

  <div class="controls">
    <button class="btn active" id="btnObtuse" onclick="setAngles(110, 110)">Two Obtuse (110° + 110°)</button>
    <button class="btn" id="btnRight" onclick="setAngles(90, 90)">Two Right (90° + 90°)</button>
    <button class="btn" id="btnValid" onclick="setAngles(110, 35)">One Obtuse (110° + 35°)</button>
  </div>

  <div class="canvas-box">
    <div id="banner" class="banner">
      <span id="bannerIcon">✕</span>
      <span id="bannerText">They spread apart! Can never connect into 3 sides!</span>
    </div>

    <svg viewBox="0 0 480 250">
      <defs>
        
        <marker id="arrow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#2563eb" />
        </marker>
        <marker id="arrow-red-left" viewBox="0 0 10 10" refX="3" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 8 1.5 L 0 5 L 8 8.5 z" fill="#ef4444" />
        </marker>
        <marker id="arrow-red-right" viewBox="0 0 10 10" refX="7" refY="5" markerWidth="6" markerHeight="6" orient="auto">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#ef4444" />
        </marker>
      </defs>

      
      <line id="gapLine" x1="100" y1="65" x2="380" y2="65" stroke="#ef4444" stroke-width="2" stroke-dasharray="5,4" opacity="1" marker-start="url(#arrow-red-left)" marker-end="url(#arrow-red-right)" />
      <text id="gapText" x="240" y="58" text-anchor="middle" font-size="12" font-weight="700" fill="#ef4444">Spreading Apart ⟷</text>

      
      <line id="rayLeft" x1="170" y1="195" x2="119" y2="59" stroke="#2563eb" stroke-width="4" stroke-linecap="round" marker-end="url(#arrow)" />
      
      
      <line id="rayRight" x1="310" y1="195" x2="361" y2="59" stroke="#2563eb" stroke-width="4" stroke-linecap="round" marker-end="url(#arrow)" />

      
      <line x1="170" y1="195" x2="310" y2="195" stroke="#1e293b" stroke-width="5" stroke-linecap="round" />
      <text x="240" y="216" text-anchor="middle" font-size="12" font-weight="600" fill="#64748b">Base</text>

      
      <path id="arcLeft" fill="rgba(37,99,235,0.12)" stroke="#2563eb" stroke-width="2" />
      <text id="textAngleLeft" x="195" y="180" font-size="13" font-weight="bold" fill="#2563eb" text-anchor="middle">110°</text>

      
      <path id="arcRight" fill="rgba(37,99,235,0.12)" stroke="#2563eb" stroke-width="2" />
      <text id="textAngleRight" x="285" y="180" font-size="13" font-weight="bold" fill="#2563eb" text-anchor="middle">110°</text>

      
      <circle cx="170" cy="195" r="5" fill="#1e293b" />
      <circle cx="310" cy="195" r="5" fill="#1e293b" />
    </svg>
  </div>

  <div class="slider-row">
    <div class="slider-group">
      <span>Left: <b id="lblLeft" style="color:#2563eb;">110°</b></span>
      <input type="range" id="slideLeft" min="30" max="130" value="110" oninput="onSlide()">
    </div>
    <div class="slider-group">
      <span>Right: <b id="lblRight" style="color:#2563eb;">110°</b></span>
      <input type="range" id="slideRight" min="30" max="130" value="110" oninput="onSlide()">
    </div>
  </div>

  <script>
    const bX1 = 170, bY1 = 195;
    const bX2 = 310, bY2 = 195;
    const rayLen = 145;

    // Helper to draw arc for interior angles
    function drawArc(cx, cy, r, startAngleDeg, endAngleDeg, isLeft) {
      const rad1 = (startAngleDeg * Math.PI) / 180;
      const rad2 = (endAngleDeg * Math.PI) / 180;
      const x1 = cx + r * Math.cos(rad1);
      const y1 = cy - r * Math.sin(rad1);
      const x2 = cx + r * Math.cos(rad2);
      const y2 = cy - r * Math.sin(rad2);
      const sweep = isLeft ? 0 : 1;
      return `M ${cx} ${cy} L ${x1} ${y1} A ${r} ${r} 0 0 ${sweep} ${x2} ${y2} Z`;
    }

    function update() {
      const aL = parseInt(document.getElementById('slideLeft').value);
      const aR = parseInt(document.getElementById('slideRight').value);

      document.getElementById('lblLeft').textContent = aL + '°';
      document.getElementById('lblRight').textContent = aR + '°';

      // Left ray math: interior angle aL from base (pointing right = 0 deg)
      // aL > 90° gives cos(aL) < 0 (dx < 0, leans left/outward)
      const radL = (aL * Math.PI) / 180;
      const xL = bX1 + rayLen * Math.cos(radL);
      const yL = bY1 - rayLen * Math.sin(radL);

      // Right ray math: interior angle aR from base (pointing left = 180 deg)
      // aR > 90° gives cos(aR) < 0, so bX2 - cos(aR) leans right/outward (dx > 0)
      const radR = (aR * Math.PI) / 180;
      const xR = bX2 - rayLen * Math.cos(radR);
      const yR = bY2 - rayLen * Math.sin(radR);

      const sum = aL + aR;

      const rL = document.getElementById('rayLeft');
      const rR = document.getElementById('rayRight');
      const gapLine = document.getElementById('gapLine');
      const gapText = document.getElementById('gapText');
      const banner = document.getElementById('banner');
      const bIcon = document.getElementById('bannerIcon');
      const bText = document.getElementById('bannerText');

      // Left arc: sweeps from 0° (base) CCW to aL
      document.getElementById('arcLeft').setAttribute('d', drawArc(bX1, bY1, 28, 0, aL, true));
      // Position left label inside the arc
      const midL = (aL / 2) * Math.PI / 180;
      document.getElementById('textAngleLeft').setAttribute('x', bX1 + 42 * Math.cos(midL));
      document.getElementById('textAngleLeft').setAttribute('y', bY1 - 42 * Math.sin(midL) + 4);
      document.getElementById('textAngleLeft').textContent = aL + '°';

      // Right arc: sweeps from 180° (base) CW to 180 - aR
      document.getElementById('arcRight').setAttribute('d', drawArc(bX2, bY2, 28, 180, 180 - aR, false));
      // Position right label inside the arc
      const midR = (180 - aR / 2) * Math.PI / 180;
      document.getElementById('textAngleRight').setAttribute('x', bX2 + 42 * Math.cos(midR));
      document.getElementById('textAngleRight').setAttribute('y', bY2 - 42 * Math.sin(midR) + 4);
      document.getElementById('textAngleRight').textContent = aR + '°';

      if (sum >= 180) {
        // Diverge or Parallel
        rL.setAttribute('x2', xL);
        rL.setAttribute('y2', yL);
        rR.setAttribute('x2', xR);
        rR.setAttribute('y2', yR);

        gapLine.setAttribute('x1', xL);
        gapLine.setAttribute('y1', yL);
        gapLine.setAttribute('x2', xR);
        gapLine.setAttribute('y2', yR);
        gapLine.setAttribute('opacity', '1');
        gapText.setAttribute('x', (xL + xR) / 2);
        gapText.setAttribute('y', Math.min(yL, yR) - 8);
        gapText.setAttribute('opacity', '1');

        if (sum === 180 && aL === 90 && aR === 90) {
          banner.className = 'banner parallel';
          bIcon.textContent = '∥';
          bText.textContent = 'Parallel! Rays run straight up & never meet.';
          gapText.textContent = 'Parallel ∥ Never Meet';
          gapText.setAttribute('fill', '#b45309');
          gapLine.setAttribute('stroke', '#f59e0b');
        } else {
          banner.className = 'banner';
          bIcon.textContent = '✕';
          bText.textContent = 'They spread apart! Can never connect into 3 sides!';
          gapText.textContent = 'Spreading Apart ⟷';
          gapText.setAttribute('fill', '#ef4444');
          gapLine.setAttribute('stroke', '#ef4444');
        }
      } else {
        // Converge to form a triangle
        const thirdAngle = (180 - sum) * Math.PI / 180;
        const baseWidth = bX2 - bX1;
        const sideB = baseWidth * Math.sin(radR) / Math.sin(thirdAngle);

        const intX = bX1 + sideB * Math.cos(radL);
        const intY = bY1 - sideB * Math.sin(radL);

        rL.setAttribute('x2', intX);
        rL.setAttribute('y2', intY);
        rR.setAttribute('x2', intX);
        rR.setAttribute('y2', intY);

        gapLine.setAttribute('opacity', '0');
        gapText.setAttribute('opacity', '0');

        banner.className = 'banner valid';
        bIcon.textContent = '✓';
        bText.textContent = `Sides meet! Valid triangle (${180 - sum}° apex).`;
      }
    }

    function setAngles(l, r) {
      document.getElementById('slideLeft').value = l;
      document.getElementById('slideRight').value = r;
      document.querySelectorAll('.btn').forEach(b => b.classList.remove('active'));
      if (l === 110 && r === 110) document.getElementById('btnObtuse').classList.add('active');
      else if (l === 90 && r === 90) document.getElementById('btnRight').classList.add('active');
      else if (l === 110 && r === 35) document.getElementById('btnValid').classList.add('active');
      update();
    }

    function onSlide() {
      document.querySelectorAll('.btn').forEach(b => b.classList.remove('active'));
      update();
    }

    update();
  </script>
</body>
</html>

OGM.4.G.1

Aligned learning resources

Related diagrams