diff --git a/src/App.js b/src/App.js
index 30e7fd6..e10fea7 100644
--- a/src/App.js
+++ b/src/App.js
@@ -23,6 +23,8 @@ export default function App() {
   const [isSending, setIsSending] = useState(false);
   const [isBotTyping, setIsBotTyping] = useState(false);
 
+  const [rethinkTargetIdx, setRethinkTargetIdx] = useState(null);
+
   const bottomRef = useRef(null);
 
   useEffect(() => {
@@ -67,6 +69,49 @@ export default function App() {
     setIsSending(false);
   }
 
+  async function handleRethink(targetIdx) {
+    if (isSending || isBotTyping) return;
+    const target = messages[targetIdx];
+    if (!target || target.role !== "assistant") return;
+
+    setRethinkTargetIdx(targetIdx);
+    setIsBotTyping(true);
+
+    // 把目标消息内容替换成占位文本
+    setMessages((prev) => {
+      const next = [...prev];
+      next[targetIdx] = { ...next[targetIdx], content: "正在重新思考…" };
+      return next;
+    });
+
+    // 用“该条 assistant 之前的历史” + 重新思考指令
+    const before = messages.slice(0, targetIdx);
+    const historyForModel = [
+      { role: "system", content: "你是一个简洁的助手，用中文回答。" },
+      ...before.map(({ role, content }) => ({ role, content })),
+      {
+        role: "user",
+        content: "我对你刚才的回答不满意。请重新思考并改进：更准确、更有条理；如有错误请纠正；尽量避免重复原句。",
+      },
+    ];
+
+    let newReply = "";
+    try {
+      newReply = await requestBotReply(historyForModel);
+    } catch (e) {
+      newReply = "重新思考失败了，请稍后再试。";
+    }
+
+    // 覆盖原来的那条 assistant 内容
+    setMessages((prev) => {
+      const next = [...prev];
+      next[targetIdx] = { ...next[targetIdx], content: newReply };
+      return next;
+    });
+    setIsBotTyping(false);
+    setRethinkTargetIdx(null);
+  }
+
   function handleKeyDown(e) {
     if (e.key === "Enter" && !e.shiftKey) {
       e.preventDefault();
@@ -78,26 +123,29 @@ export default function App() {
     <div className="min-h-screen bg-gradient-to-b from-background to-content2/50 p-4">
       <div className="mx-auto max-w-3xl">
         <Card className="shadow-xl">
-          {/* 顶部 */}
-          <CardHeader className="flex items-center">
-            <div className="flex flex-col">
-              <span className="font-semibold">Chatbot Demo</span>
-              <span className="text-xs text-default-500">
-              </span>
-            </div>
+          <CardHeader>
+            <span className="font-semibold">Chatbot Demo</span>
           </CardHeader>
 
           <Divider />
 
-          {/* 聊天区域 */}
           <CardBody className="p-0">
             <ScrollShadow className="h-[520px] px-4 py-4">
-              <div className="flex flex-col gap-3">
-                {messages.map((m) => {
+              <div className="flex flex-col gap-4">
+                {messages.map((m, idx) => {
                   const isUser = m.role === "user";
+                  const isAssistant = m.role === "assistant";
+                  const isInitialGreeting = idx === 0;
+                  const canRethink = isAssistant && !isInitialGreeting;
+
                   return (
-                    <div className={`flex ${isUser ? "justify-end" : "justify-start"}`} >
-                      <div className={`flex max-w-[80%] ${isUser ? "flex-row-reverse" : ""}`} >
+                    <div
+                      key={idx}
+                      className={`flex ${isUser ? "justify-end" : "justify-start"}`}
+                    >
+                      {/* 以气泡为参照：按钮放在气泡“下面的右侧” */}
+                      <div className="relative max-w-[80%]">
+                        {/* 气泡 */}
                         <div
                           className={`rounded-2xl px-4 py-3 text-sm leading-relaxed ${isUser
                             ? "bg-primary text-primary-foreground"
@@ -106,18 +154,51 @@ export default function App() {
                         >
                           {m.content}
                         </div>
+
+                        {/* 在气泡下方*/}
+                        {canRethink && (
+                          <button
+                            type="button"
+                            title="重新思考"
+                            disabled={isSending || isBotTyping}
+                            onClick={() => handleRethink(idx)}
+                            className="
+                              absolute
+                              right-0
+                              top-full
+                              mt-2
+                              h-7
+                              w-7
+                              rounded-full
+                              border
+                              border-default-200
+                              bg-background
+                              text-default-500
+                              text-sm
+                              shadow-sm
+                              hover:bg-content2
+                              hover:text-foreground
+                              disabled:opacity-40
+                              disabled:cursor-not-allowed
+                            "
+                          >
+                            <span className={rethinkTargetIdx === idx ? "inline-block animate-spin" : ""}>
+                              ↻
+                            </span>
+                          </button>
+                        )}
                       </div>
                     </div>
                   );
                 })}
 
-                {isBotTyping && (
+
+                {/* 全局“正在回复…” */}
+                {isBotTyping && rethinkTargetIdx === null && (
                   <div className="flex justify-start">
-                    <div className="flex items-center">
-                      <div className="flex items-center gap-2 rounded-2xl bg-content2 px-4 py-2 text-sm text-default-600">
-                        <Spinner size="sm" />
-                        正在回复…
-                      </div>
+                    <div className="flex items-center gap-2 rounded-2xl bg-content2 px-4 py-2 text-sm text-default-600">
+                      <Spinner size="sm" />
+                      正在回复…
                     </div>
                   </div>
                 )}
@@ -130,35 +211,32 @@ export default function App() {
 
             {/* 输入区 */}
             <div className="p-4">
-              {/* 这个容器视觉上就是“一个输入框” */}
               <div className="rounded-xl border border-default-200 bg-background shadow-sm">
-                {/* 上半部分：真正可滚动/可拖拉的 textarea */}
                 <div className="px-3 pt-3">
                   <textarea
                     value={inputText}
                     onChange={(e) => setInputText(e.target.value)}
                     onKeyDown={handleKeyDown}
                     placeholder="输入消息，Enter 发送，Shift+Enter 换行"
-                    disabled={isSending}
+                    disabled={isSending || isBotTyping}
                     rows={2}
                     className="
                     w-full bg-transparent outline-none
                     text-sm leading-relaxed text-foreground
                     placeholder:text-default-400
-                    resize-y
+                    resize-none
                     min-h-[72px] max-h-[220px]
                     overflow-auto
                   "
                   />
                 </div>
 
-                {/* 下半部分：输入框“内部”的工具栏，按钮在右下角 */}
-                <div className="flex items-center justify-end gap-2 px-3 py-2">
+                <div className="flex justify-end px-3 py-2">
                   <Button
                     color="primary"
                     size="sm"
                     onPress={handleSend}
-                    isDisabled={isSending || !inputText.trim()}
+                    isDisabled={isSending || isBotTyping || !inputText.trim()}
                   >
                     {isSending ? "发送中…" : "发送"}
                   </Button>
@@ -170,4 +248,4 @@ export default function App() {
       </div>
     </div>
   );
-}
+}
\ No newline at end of file