diff --git a/src/app/chat/components/__tests__/tailwind-components.test.tsx b/src/app/chat/components/__tests__/tailwind-components.test.tsx
new file mode 100644
index 00000000..dce97b4f
--- /dev/null
+++ b/src/app/chat/components/__tests__/tailwind-components.test.tsx
@@ -0,0 +1,40 @@
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it } from "vitest";
+
+import { MessageAvatar } from "../message-avatar";
+import { TextBubble } from "../text-bubble";
+
+describe("chat Tailwind components", () => {
+  it("renders MessageAvatar AI and user branches with image utilities", () => {
+    const aiHtml = renderToStaticMarkup(<MessageAvatar isFromAI={true} />);
+    const userHtml = renderToStaticMarkup(
+      <MessageAvatar isFromAI={false} userAvatarUrl="/user-avatar.png" />,
+    );
+
+    expect(aiHtml).toContain('aria-label="AI avatar"');
+    expect(aiHtml).toContain("size-[var(--chat-avatar-size,43px)]");
+    expect(aiHtml).toContain("size-full object-cover");
+    expect(aiHtml).toContain("%2Fimages%2Fchat%2Fpic-chat-elio.png");
+    expect(userHtml).toContain('aria-label="User avatar"');
+    expect(userHtml).toContain("%2Fuser-avatar.png");
+  });
+
+  it("renders TextBubble AI and user visual variants", () => {
+    const aiHtml = renderToStaticMarkup(
+      <TextBubble content={"hello\nthere"} isFromAI={true} />,
+    );
+    const userHtml = renderToStaticMarkup(
+      <TextBubble content="from user" isFromAI={false} />,
+    );
+
+    expect(aiHtml).toContain("whitespace-pre-wrap");
+    expect(aiHtml).toContain("rounded-tl-none");
+    expect(aiHtml).toContain("bg-white");
+    expect(aiHtml).toContain("hello\nthere");
+    expect(userHtml).toContain("rounded-tr-none");
+    expect(userHtml).toContain(
+      "bg-[linear-gradient(to_right,var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))]",
+    );
+    expect(userHtml).toContain("from user");
+  });
+});
diff --git a/src/app/chat/components/message-avatar.module.css b/src/app/chat/components/message-avatar.module.css
deleted file mode 100644
index 8ab326fc..00000000
--- a/src/app/chat/components/message-avatar.module.css
+++ /dev/null
@@ -1,30 +0,0 @@
-/* MessageAvatar 头像样式 */
-
-.avatar {
-  flex: 0 0 auto;
-  width: var(--chat-avatar-size, 43px);
-  height: var(--chat-avatar-size, 43px);
-  border-radius: 9999px;
-  overflow: hidden;
-  border: 2px solid var(--color-avatar-border, #fbf3f5);
-  box-shadow: var(--shadow-input-box, 0 1px 2px rgba(0, 0, 0, 0.1));
-  background: var(--color-avatar-border, #fbf3f5);
-  display: flex;
-  align-items: center;
-  justify-content: center;
-}
-
-.avatar img {
-  width: 100%;
-  height: 100%;
-  object-fit: cover;
-}
-
-.placeholder {
-  width: 100%;
-  height: 100%;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  font-size: var(--icon-size-xl, 24px);
-}
diff --git a/src/app/chat/components/message-avatar.tsx b/src/app/chat/components/message-avatar.tsx
index 1a189bf8..ad3b7365 100644
--- a/src/app/chat/components/message-avatar.tsx
+++ b/src/app/chat/components/message-avatar.tsx
@@ -2,23 +2,26 @@
 import Image from "next/image";
 
 import { UserMessageAvatar } from "@/app/_components";
-import styles from "./message-avatar.module.css";
 
 export interface MessageAvatarProps {
   isFromAI: boolean;
   userAvatarUrl?: string | null;
 }
 
+const AVATAR_CLASS_NAME =
+  "flex size-[var(--chat-avatar-size,43px)] shrink-0 items-center justify-center overflow-hidden rounded-full border-2 border-[var(--color-avatar-border,#fbf3f5)] bg-[var(--color-avatar-border,#fbf3f5)] shadow-[var(--shadow-input-box,0_1px_2px_rgba(0,0,0,0.1))]";
+
 export function MessageAvatar({ isFromAI, userAvatarUrl }: MessageAvatarProps) {
   if (isFromAI) {
     return (
-      <div className={styles.avatar} aria-label="AI avatar">
+      <div className={AVATAR_CLASS_NAME} aria-label="AI avatar">
         <Image
           src="/images/chat/pic-chat-elio.png"
           alt="Elio"
           width={43}
           height={43}
           priority
+          className="size-full object-cover"
         />
       </div>
     );
diff --git a/src/app/chat/components/text-bubble.module.css b/src/app/chat/components/text-bubble.module.css
deleted file mode 100644
index bfe00367..00000000
--- a/src/app/chat/components/text-bubble.module.css
+++ /dev/null
@@ -1,30 +0,0 @@
-/* TextBubble 文字气泡样式 */
-
-.bubble {
-  /* 撑满父（MessageContent column 宽）—— 让气泡占满所在半区 */
-  width: 100%;
-  align-self: stretch;
-  padding: var(--spacing-3, 12px) var(--spacing-4, 16px);
-  border-radius: var(--radius-xxl, 24px);
-  font-size: var(--chat-message-font-size, var(--responsive-body, 16px));
-  line-height: var(--chat-message-line-height, 1.5);
-  white-space: pre-wrap;
-  word-break: break-word;
-  box-shadow: var(--shadow-input-box, 0 1px 2px rgba(0, 0, 0, 0.1));
-}
-
-.bubbleAi {
-  background: #fff;
-  color: var(--color-text-foreground, #000);
-  border-top-left-radius: 0;
-}
-
-.bubbleUser {
-  background: linear-gradient(
-    to right,
-    var(--color-button-gradient-start, #ff67e0),
-    var(--color-button-gradient-end, #ff52a2)
-  );
-  color: #fff;
-  border-top-right-radius: 0;
-}
diff --git a/src/app/chat/components/text-bubble.tsx b/src/app/chat/components/text-bubble.tsx
index 31c84fcb..84d77338 100644
--- a/src/app/chat/components/text-bubble.tsx
+++ b/src/app/chat/components/text-bubble.tsx
@@ -8,17 +8,27 @@
  *   - AI 消息：白底黑字 + 左上角尖角
  *   - 用户消息：渐变（primaryGradient）+ 白字 + 右上角尖角
  */
-import styles from "./text-bubble.module.css";
 
 export interface TextBubbleProps {
   content: string;
   isFromAI: boolean;
 }
 
+const BASE_CLASS_NAME =
+  "w-full self-stretch whitespace-pre-wrap break-words rounded-[var(--radius-xxl,24px)] px-[var(--spacing-4,16px)] py-[var(--spacing-3,12px)] text-[length:var(--chat-message-font-size,var(--responsive-body,16px))] leading-[var(--chat-message-line-height,1.5)] shadow-[var(--shadow-input-box,0_1px_2px_rgba(0,0,0,0.1))]";
+
+const AI_CLASS_NAME =
+  "rounded-tl-none bg-white text-[var(--color-text-foreground,#000)]";
+
+const USER_CLASS_NAME =
+  "rounded-tr-none bg-[linear-gradient(to_right,var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))] text-white";
+
 export function TextBubble({ content, isFromAI }: TextBubbleProps) {
   return (
     <div
-      className={`${styles.bubble} ${isFromAI ? styles.bubbleAi : styles.bubbleUser}`}
+      className={[BASE_CLASS_NAME, isFromAI ? AI_CLASS_NAME : USER_CLASS_NAME]
+        .filter(Boolean)
+        .join(" ")}
     >
       {content}
     </div>