diff --git a/js/main.js b/js/main.js
index 3307cf2..883a182 100644
--- a/js/main.js
+++ b/js/main.js
@@ -379,39 +379,59 @@ async function loadWiki() {
         const subtopicsDiv = topicDiv.querySelector('.wiki-subtopics');
         const topicTitle = topicDiv.querySelector('.topic-title');
         
-        // Topics start collapsed
+        // All topics start collapsed
         subtopicsDiv.classList.add('hidden');
         
-        // Toggle topic on click
+        // Track open state for this topic
+        let isOpen = false;
+        let openSubtopicIndex = -1;
+        
+        // Toggle topic: click opens/closes subtopics, closes other topics
         topicTitle.onclick = () => {
-          console.log('Topic clicked:', topicName, 'current hidden:', subtopicsDiv.classList.contains('hidden'));
-          if (subtopicsDiv.classList.contains('hidden')) {
-            subtopicsDiv.classList.remove('hidden');
-          } else {
+          // Close all other topics first
+          document.querySelectorAll('.wiki-subtopics:not(.hidden)').forEach(otherSubtopics => {
+            if (otherSubtopics !== subtopicsDiv) {
+              otherSubtopics.classList.add('hidden');
+            }
+          });
+          
+          if (isOpen) {
             subtopicsDiv.classList.add('hidden');
+            isOpen = false;
+          } else {
+            subtopicsDiv.classList.remove('hidden');
+            isOpen = true;
           }
         };
         
-        subtopics.forEach(sub => {
+        subtopics.forEach((sub, index) => {
           const subtopicTitle = isEN && sub.subtopic_en ? sub.subtopic_en : sub.subtopic;
           const subtopicContent = isEN && sub.wiki_en ? sub.wiki_en : sub.wiki;
           const subtopicDiv = document.createElement('div');
           subtopicDiv.className = 'wiki-subtopic';
           subtopicDiv.innerHTML = `
             <div class="wiki-subtopic-title">${subtopicTitle || ''}</div>
-            <div class="wiki-subtopic-content">
+            <div class="wiki-subtopic-content hidden">
               <p>${subtopicContent || ''}</p>
             </div>
           `;
           subtopicsDiv.appendChild(subtopicDiv);
           
           const title = subtopicDiv.querySelector('.wiki-subtopic-title');
+          const content = subtopicDiv.querySelector('.wiki-subtopic-content');
+          
           title.onclick = (e) => {
             e.stopPropagation();
+            
+            // Close other subtopics in this topic
             subtopicsDiv.querySelectorAll('.wiki-subtopic').forEach(s => {
-              if (s !== subtopicDiv) s.classList.add('hidden');
+              if (s !== subtopicDiv) {
+                s.querySelector('.wiki-subtopic-content').classList.add('hidden');
+              }
             });
-            subtopicDiv.classList.toggle('hidden');
+            
+            // Toggle this subtopic's content
+            content.classList.toggle('hidden');
           };
         });
       }