feat: add emerald material for week 3 task 1 in vanilla

Week-3/Task-1/vanilla/index.html

@@ -10,6 +10,7 @@
     <button data-variant="black" class="active">Black</button>
     <button data-variant="silver">Silver</button>
     <button data-variant="gold">Gold</button>
+    <button data-variant="emerald">Emerald</button>
   </div>
 
   <script type="module" src="./main.js"></script>

Week-3/Task-1/vanilla/main.js

@@ -34,6 +34,11 @@ const materials = {
     roughness: 0.4,
     metalness: 1,
   }),
+  emerald: new THREE.MeshStandardMaterial({
+    color: "#009B77",
+    roughness: 0.4,
+    metalness: 1,
+  }),
 };
 
 const sphere = new THREE.Mesh(geometry, materials.black);

Week-3/Task-1/vanilla/style.css

@@ -0,0 +1,42 @@
+body {
+  margin: 0;
+  overflow: hidden;
+  font-family: 'Inter', system-ui, -apple-system, sans-serif;
+}
+
+#controls {
+  position: absolute;
+  top: 20px;
+  left: 20px;
+  display: flex;
+  gap: 12px;
+  background: rgba(255, 255, 255, 0.8);
+  backdrop-filter: blur(10px);
+  padding: 16px;
+  border-radius: 12px;
+  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
+  border: 1px solid rgba(0, 0, 0, 0.05);
+}
+
+button {
+  padding: 10px 18px;
+  border: none;
+  border-radius: 8px;
+  background: white;
+  color: #333;
+  cursor: pointer;
+  font-weight: 500;
+  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
+  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
+}
+
+button:hover {
+  transform: translateY(-2px);
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
+}
+
+button.active {
+  background: #333;
+  color: white;
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+}