diff --git a/works/ai-chat-app/www/style.css b/works/ai-chat-app/www/style.css
index d6148d3..46ae9bd 100644
--- a/works/ai-chat-app/www/style.css
+++ b/works/ai-chat-app/www/style.css
@@ -326,7 +326,16 @@ body {
   display: flex;
   flex-direction: column;
   gap: 8px;
-  max-width: 75%;
+}
+
+/* 用户消息更宽 */
+.message.user .message-body {
+  max-width: 85%;
+}
+
+/* AI 消息稍窄 */
+.message.assistant .message-body {
+  max-width: 80%;
 }
 
 .message.user .message-body {