diff --git a/js/components/chat-area.js b/js/components/chat-area.js
index 7743af3..b9abb5a 100644
--- a/js/components/chat-area.js
+++ b/js/components/chat-area.js
@@ -221,7 +221,7 @@ export function appendMessageDOM(msg, index) {
 
 /** 更新最后一条 assistant 消息（流式输出） */
 export function updateLastAssistantMessage(content, think, stats, model) {
-    const lastMsg = messagesContainerEl.querySelector('.message.assistant:last-child');
+    const lastMsg = messagesContainerEl.querySelector('.message.assistant:last-of-type');
     if (!lastMsg) return;
 
     const loadingDots = lastMsg.querySelector('.loading-dots');
diff --git a/js/components/input-area.js b/js/components/input-area.js
index 436a6a1..7411eae 100644
--- a/js/components/input-area.js
+++ b/js/components/input-area.js
@@ -511,7 +511,7 @@ ${ragContext}
         console.error('[InputArea] 流式聊天错误:', err);
 
         if (err.name === 'AbortError') {
-            const placeholder = document.querySelector('#messagesContainer .message.assistant:last-child');
+            const placeholder = document.querySelector('#messagesContainer .message.assistant:last-of-type');
             const loadingDots = placeholder?.querySelector('.loading-dots');
             const loadingText = placeholder?.querySelector('.loading-text');
             if (loadingDots) loadingDots.remove();
@@ -547,7 +547,7 @@ ${ragContext}
             return;
         }
 
-        const placeholder = document.querySelector('#messagesContainer .message.assistant:last-child');
+        const placeholder = document.querySelector('#messagesContainer .message.assistant:last-of-type');
         const loadingDots = placeholder?.querySelector('.loading-dots');
         const loadingText = placeholder?.querySelector('.loading-text');
         if (loadingDots) loadingDots.remove();