✨ Add collapsible group component with styles and animations

code/websites/pokedex.online/src/views/ChallongeTest.vue

@@ -1039,6 +1039,68 @@ h2 {
   gap: 0.5rem;
 }
 
+/* Collapsible Groups */
+.collapsible-group {
+  border: 2px solid #e9ecef;
+  border-radius: 8px;
+  padding: 0;
+  overflow: hidden;
+  transition: all 0.3s ease;
+}
+
+.collapsible-group:hover {
+  border-color: #667eea;
+  box-shadow: 0 2px 8px rgba(102, 126, 234, 0.1);
+}
+
+.collapsible-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 1rem;
+  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
+  cursor: pointer;
+  user-select: none;
+  transition: background 0.2s ease;
+}
+
+.collapsible-header:hover {
+  background: linear-gradient(135deg, #e9ecef 0%, #dee2e6 100%);
+}
+
+.collapsible-header .control-label {
+  margin: 0;
+  font-size: 1rem;
+  font-weight: 700;
+  color: #495057;
+}
+
+.collapse-icon {
+  font-size: 0.875rem;
+  color: #667eea;
+  font-weight: bold;
+  transition: transform 0.2s ease;
+}
+
+.collapsible-content {
+  padding: 1rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+  animation: slideDown 0.3s ease-out;
+}
+
+@keyframes slideDown {
+  from {
+    opacity: 0;
+    transform: translateY(-10px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
 .control-label {
   font-weight: 600;
   color: #495057;