diff --git a/src/App.vue b/src/App.vue
index 80e5519..469db46 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -1,5 +1,7 @@
 <script setup>
 import { computed, nextTick, onBeforeUnmount, onMounted, ref, watch } from 'vue'
+import baiduMark from './assets/baidu-cloud-mark.svg'
+import baiduChatMark from './assets/baidu2.png'
 
 const apiBase = ref(import.meta.env.VITE_API_BASE || 'http://127.0.0.1:9000')
 const authBase = ref(import.meta.env.VITE_AUTH_BASE || apiBase.value)
@@ -18,10 +20,13 @@ const registerPending = ref(false)
 const registerRequestId = ref(0)
 const registerStatusMessage = ref('')
 const codeCountdown = ref(0)
+const hasSentVerificationCode = ref(false)
 
 const text = ref('')
 const messages = ref([])
 const sending = ref(false)
+const assistantThinking = ref(false)
+const assistantBaselineCount = ref(0)
 const streamState = ref('disconnected')
 const messagesEl = ref(null)
 
@@ -60,6 +65,19 @@ function pushMessage(role, content, kind = 'message') {
   })
 }
 
+function countAssistantMessages(list) {
+  return list.filter((m) => m.role === 'assistant' && m.kind !== 'error').length
+}
+
+function startAssistantThinking() {
+  assistantBaselineCount.value = countAssistantMessages(messages.value)
+  assistantThinking.value = true
+}
+
+function stopAssistantThinking() {
+  assistantThinking.value = false
+}
+
 function scrollToBottom(smooth = true) {
   nextTick(() => {
     if (!messagesEl.value) return
@@ -113,6 +131,23 @@ function clearSession() {
   registerStatusMessage.value = ''
   codeCountdown.value = 0
   streamState.value = 'disconnected'
+  assistantThinking.value = false
+  assistantBaselineCount.value = 0
+}
+
+function switchAuthMode(mode) {
+  authMode.value = mode
+  authError.value = ''
+  registerStatusMessage.value = ''
+  registerPending.value = false
+  if (mode === 'login') {
+    hasSentVerificationCode.value = false
+    codeCountdown.value = 0
+    if (codeCountdownTimer) {
+      clearInterval(codeCountdownTimer)
+      codeCountdownTimer = null
+    }
+  }
 }
 
 function startCodeCountdown() {
@@ -120,7 +155,7 @@ function startCodeCountdown() {
     clearInterval(codeCountdownTimer)
     codeCountdownTimer = null
   }
-  codeCountdown.value = 120
+  codeCountdown.value = 180
   codeCountdownTimer = setInterval(() => {
     if (codeCountdown.value <= 1) {
       codeCountdown.value = 0
@@ -134,6 +169,45 @@ function startCodeCountdown() {
   }, 1000)
 }
 
+async function sendVerificationCode() {
+  const phone = loginPhone.value.trim()
+  const password = loginPassword.value
+  if (!/^\d{6,20}$/.test(phone)) {
+    authError.value = '请先输入有效手机号'
+    return
+  }
+  if (!password) {
+    authError.value = '请先输入密码'
+    return
+  }
+
+  if (!localAuthOnly.value) {
+    try {
+      const resp = await fetch(`${authBase.value}/auth/send-code`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ phone, password }),
+      })
+      const payload = await resp.json().catch(() => ({}))
+      if (!resp.ok || !payload.ok) {
+        authError.value = payload.detail || payload.error || '验证码发送失败'
+        return
+      }
+      registerStatusMessage.value = payload.message || '验证码已发送，请在 180 秒内完成注册'
+    } catch (err) {
+      authError.value = String(err)
+      return
+    }
+  }
+
+  authError.value = ''
+  hasSentVerificationCode.value = true
+  if (localAuthOnly.value) {
+    registerStatusMessage.value = '验证码已发送，请在 180 秒内完成注册'
+  }
+  startCodeCountdown()
+}
+
 function startRegisterStatusPolling() {
   if (registerPollTimer) {
     clearInterval(registerPollTimer)
@@ -258,6 +332,11 @@ async function register() {
   authLoading.value = true
   authError.value = ''
   registerStatusMessage.value = ''
+  if (!hasSentVerificationCode.value) {
+    authError.value = '请先点击“发送”获取验证码'
+    authLoading.value = false
+    return
+  }
   try {
     const resp = await fetch(`${authBase.value}/auth/register`, {
       method: 'POST',
@@ -277,7 +356,7 @@ async function register() {
     registerPending.value = true
     registerRequestId.value = Number(payload.request_id || 0)
     registerStatusMessage.value = '待后端验证'
-    startCodeCountdown()
+    hasSentVerificationCode.value = false
     startRegisterStatusPolling()
   } catch (err) {
     authError.value = String(err)
@@ -361,6 +440,9 @@ async function loadHistory() {
         seenMessages.add(messageSignature(m.role, m.content, m.kind, m.at))
       }
       messages.value = nextMessages
+      if (assistantThinking.value && countAssistantMessages(nextMessages) > assistantBaselineCount.value) {
+        stopAssistantThinking()
+      }
       scrollToBottom(false)
     }
   } catch (_) {
@@ -401,6 +483,9 @@ function connectStream() {
         kind,
         at,
       })
+      if (role === 'assistant') {
+        stopAssistantThinking()
+      }
     } catch (_) {
       // Ignore malformed payload and keep the stream alive.
     }
@@ -431,13 +516,16 @@ async function sendMessage() {
 
     if (!resp.ok) {
       const detail = await resp.text()
+      stopAssistantThinking()
       pushMessage('system', `Send failed: ${detail || resp.statusText}`, 'error')
     } else {
+      startAssistantThinking()
       setTimeout(() => {
         loadHistory()
       }, 800)
     }
   } catch (err) {
+    stopAssistantThinking()
     pushMessage('system', `Send failed: ${String(err)}`, 'error')
   } finally {
     text.value = ''
@@ -458,6 +546,15 @@ watch(
   },
 )
 
+watch(
+  () => assistantThinking.value,
+  (thinking) => {
+    if (thinking) {
+      scrollToBottom(true)
+    }
+  },
+)
+
 onBeforeUnmount(() => {
   if (eventSource) eventSource.close()
   if (historyPollTimer) clearInterval(historyPollTimer)
@@ -470,112 +567,133 @@ onBeforeUnmount(() => {
   <main class="screen">
     <section v-if="!isLoggedIn" class="auth-shell">
       <header class="top-bar">
-        <div>
-          <h1>nanobot login</h1>
-          <p>Use phone + password to access your chat workspace</p>
+        <div class="auth-headline">
+          <img class="auth-logo" :src="baiduMark" alt="Baidu AI+" />
+          <div>
+            <h1>欢迎使用百度 AI+ 教育智能助手</h1>
+            <p>请输入手机号和密码登录，首次注册需输入验证码并验证</p>
+          </div>
         </div>
       </header>
 
       <div class="auth-form">
-        <label>
-          phone
-          <input v-model="loginPhone" placeholder="e.g. 13800000000" />
-        </label>
-        <label>
-          password
-          <input v-model="loginPassword" type="password" placeholder="at least 6 chars" />
-        </label>
-        <label v-if="!localAuthOnly">
-          verification code
-          <input v-model="verificationCode" placeholder="请输入验证码" />
-        </label>
+        <template v-if="authMode === 'login'">
+          <label>
+            手机号
+            <input v-model="loginPhone" placeholder="请输入手机号，例如 13800000000" />
+          </label>
+          <label>
+            密码
+            <input v-model="loginPassword" type="password" placeholder="请输入登录密码" />
+          </label>
+        </template>
+
+        <template v-else>
+          <label>
+            手机号
+            <input v-model="loginPhone" placeholder="请输入手机号，例如 13800000000" />
+          </label>
+          <label>
+            密码
+            <input v-model="loginPassword" type="password" placeholder="请设置登录密码" />
+          </label>
+          <label v-if="!localAuthOnly">
+            验证码
+            <div class="inline-field">
+              <input v-model="verificationCode" placeholder="请输入验证码" />
+              <button
+                type="button"
+                class="send-code-btn"
+                :disabled="codeCountdown > 0 || authLoading"
+                @click="sendVerificationCode"
+              >
+                {{ codeCountdown > 0 ? `${codeCountdown}s` : '发送' }}
+              </button>
+            </div>
+          </label>
+        </template>
+
+        <div class="ai-tags">
+          <span class="ai-tag">百度 AI+</span>
+          <span class="ai-tag">智能问答</span>
+          <span class="ai-tag">实时会话</span>
+        </div>
 
         <div class="auth-actions">
-          <button :disabled="authLoading" @click="login">Login</button>
-          <button class="reconnect" :disabled="authLoading" @click="register">Register</button>
+          <button v-if="authMode === 'login'" :disabled="authLoading" @click="login">登录</button>
+          <button v-if="authMode === 'register'" :disabled="authLoading || registerPending" @click="register">提交注册</button>
+          <button
+            v-if="authMode === 'login'"
+            type="button"
+            class="reconnect"
+            :disabled="authLoading"
+            @click="switchAuthMode('register')"
+          >
+            注册账号
+          </button>
+          <button
+            v-if="authMode === 'register'"
+            type="button"
+            class="reconnect"
+            :disabled="authLoading"
+            @click="switchAuthMode('login')"
+          >
+            返回登录
+          </button>
         </div>
 
         <p class="auth-error" v-if="authError">{{ authError }}</p>
         <p class="auth-error" v-if="registerPending || registerStatusMessage">
-          {{ registerStatusMessage || '待后端验证' }}
-        </p>
-        <p class="auth-error" v-if="registerPending && codeCountdown > 0">
-          验证码倒计时：{{ codeCountdown }}s
+          {{ registerStatusMessage || '请等待验证' }}
         </p>
       </div>
     </section>
 
     <section v-else class="chat-shell">
-      <div class="workspace">
-        <aside class="workspace-sidebar">
-          <div class="sidebar-brand">
-            <h2>nanobot</h2>
-            <p>AI workspace</p>
-          </div>
-
-          <div class="sidebar-card">
-            <span class="card-label">Account</span>
-            <strong>{{ currentUser?.phone }}</strong>
-            <span class="badge" :class="streamState">{{ streamState }}</span>
-            <div class="sidebar-actions">
-              <button class="reconnect" @click="connectStream">Reconnect</button>
-              <button class="reconnect" @click="clearSession">Logout</button>
+      <section class="workspace-main">
+        <header class="main-head">
+          <div class="main-head-brand">
+            <img class="chat-logo" :src="baiduChatMark" alt="Baidu" />
+            <div>
+              <h1>百度 AI+ 教育智能助手</h1>
+              <p>欢迎与我实时交流</p>
             </div>
           </div>
-
-          <div class="config-panel">
-            <label>
-              API
-              <input v-model="apiBase" placeholder="http://127.0.0.1:9000" />
-            </label>
-            <label v-if="!localAuthOnly">
-              AUTH API
-              <input v-model="authBase" placeholder="http://127.0.0.1:9100" />
-            </label>
-            <label>
-              sender
-              <input v-model="senderId" placeholder="web-user" />
-            </label>
-            <label>
-              chat
-              <input v-model="chatId" placeholder="web-user" />
-            </label>
-            <label v-if="!localAuthOnly">
-              token
-              <input v-model="apiToken" placeholder="Bearer token" readonly />
-            </label>
+          <div class="main-head-actions">
+            <span class="badge" :class="streamState">{{ streamState }}</span>
+            <button class="reconnect" @click="connectStream">重连</button>
+            <button class="reconnect" @click="clearSession">退出</button>
           </div>
-        </aside>
+        </header>
 
-        <section class="workspace-main">
-          <header class="main-head">
-            <h1>智能对话</h1>
-            <p>和 nanobot 的实时会话</p>
-          </header>
+        <div class="messages" ref="messagesEl">
+          <article
+            v-for="msg in messages"
+            :key="msg.id"
+            class="bubble"
+            :class="[msg.role, msg.kind]"
+          >
+            <p>{{ msg.content }}</p>
+            <small>{{ msg.at }}</small>
+          </article>
+          <article v-if="assistantThinking" class="bubble assistant thinking">
+            <p>
+              <span class="thinking-spinner" aria-hidden="true"></span>
+              智能助手正在思考...
+            </p>
+          </article>
+        </div>
 
-          <div class="messages" ref="messagesEl">
-            <article
-              v-for="msg in messages"
-              :key="msg.id"
-              class="bubble"
-              :class="[msg.role, msg.kind]"
-            >
-              <p>{{ msg.content }}</p>
-              <small>{{ msg.role }} · {{ msg.at }}</small>
-            </article>
-          </div>
-
-          <footer class="composer">
-            <textarea
-              v-model="text"
-              rows="2"
-              placeholder="给 nanobot 发送消息"
-              @keydown.enter.exact.prevent="sendMessage"
-            />
-            <button :disabled="!canSend" @click="sendMessage">发送</button>
-          </footer>
-        </section>
-      </div>
+        <footer class="composer">
+          <textarea
+            v-model="text"
+            rows="2"
+            placeholder="给 nanobot 发送消息"
+            @keydown.enter.exact.prevent="sendMessage"
+          />
+          <button :disabled="!canSend" @click="sendMessage">发送</button>
+        </footer>
+      </section>
     </section>
   </main>
 </template>
diff --git a/src/assets/baidu-cloud-mark.svg b/src/assets/baidu-cloud-mark.svg
new file mode 100644
index 0000000..3c94040
--- /dev/null
+++ b/src/assets/baidu-cloud-mark.svg
@@ -0,0 +1,21 @@
+<svg width="240" height="180" viewBox="0 0 240 180" xmlns="http://www.w3.org/2000/svg" role="img" aria-label="Baidu Cloud style mark">
+  <defs>
+    <linearGradient id="b1" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#31C8E8"/>
+      <stop offset="100%" stop-color="#1B96DE"/>
+    </linearGradient>
+    <linearGradient id="b2" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#FF6B8A"/>
+      <stop offset="100%" stop-color="#F04A79"/>
+    </linearGradient>
+  </defs>
+
+  <circle cx="120" cy="60" r="36" fill="none" stroke="url(#b1)" stroke-width="16"/>
+  <circle cx="73" cy="92" r="30" fill="none" stroke="url(#b1)" stroke-width="16"/>
+  <path d="M 130 96 C 165 96 175 135 151 148" fill="none" stroke="url(#b1)" stroke-width="16" stroke-linecap="round"/>
+  <path d="M 93 80 C 98 90 110 95 120 95 C 130 95 142 90 147 80" fill="none" stroke="url(#b2)" stroke-width="14" stroke-linecap="round"/>
+
+  <text x="120" y="168" text-anchor="middle" font-size="26" font-family="'Noto Sans SC', sans-serif" fill="#2C67D9" font-weight="700">
+    百度 AI+
+  </text>
+</svg>
diff --git a/src/assets/baidu2.png b/src/assets/baidu2.png
new file mode 100644
index 0000000..2003477
Binary files /dev/null and b/src/assets/baidu2.png differ
diff --git a/src/style.css b/src/style.css
index 3fe9e36..0bcb343 100644
--- a/src/style.css
+++ b/src/style.css
@@ -113,14 +113,38 @@ body {
   display: grid;
   grid-template-rows: auto 1fr auto;
   background: rgba(255, 255, 255, 0.58);
+  min-height: calc(100vh - 2.4rem);
 }
 
 .main-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 0.9rem;
   padding: 1rem 1.2rem 0.7rem;
   border-bottom: 1px solid var(--line);
   background: rgba(255, 255, 255, 0.72);
 }
 
+.main-head-brand {
+  display: flex;
+  align-items: center;
+  gap: 0.72rem;
+}
+
+.chat-logo {
+  width: 168px;
+  height: 44px;
+  object-fit: contain;
+  flex-shrink: 0;
+}
+
+.main-head-actions {
+  display: flex;
+  align-items: center;
+  gap: 0.45rem;
+}
+
 .main-head h1 {
   margin: 0;
   font-size: 1.08rem;
@@ -148,6 +172,69 @@ body {
   gap: 0.7rem;
 }
 
+.auth-headline {
+  display: flex;
+  gap: 0.85rem;
+  align-items: center;
+}
+
+.auth-logo {
+  width: 82px;
+  height: 64px;
+  object-fit: contain;
+  flex-shrink: 0;
+}
+
+.auth-headline h1 {
+  margin: 0;
+  font-size: 1.06rem;
+  line-height: 1.35;
+}
+
+.auth-headline p {
+  margin: 0.22rem 0 0;
+  color: var(--ink-soft);
+  font-size: 0.85rem;
+  line-height: 1.4;
+}
+
+.ai-tags {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.4rem;
+}
+
+.ai-tag {
+  border: 1px solid #c8d9fb;
+  background: #f1f6ff;
+  color: #2f67dc;
+  padding: 0.22rem 0.52rem;
+  border-radius: 999px;
+  font-size: 0.75rem;
+  font-weight: 600;
+}
+
+.inline-field {
+  display: grid;
+  gap: 0.5rem;
+  grid-template-columns: 1fr auto;
+  align-items: center;
+}
+
+.send-code-btn {
+  min-width: 84px;
+  background: #f3f7ff;
+  color: var(--brand);
+  border: 1px solid #c7d8fb;
+  font-weight: 600;
+}
+
+.send-code-btn:disabled {
+  background: #eef1f7;
+  color: #93a2bb;
+  border-color: #d6deea;
+}
+
 .auth-actions {
   display: flex;
   gap: 0.55rem;
@@ -280,6 +367,32 @@ textarea:focus {
   background: #fff3f3;
 }
 
+.bubble.thinking {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.5rem;
+  background: #f7faff;
+  border-color: #c8d8f6;
+}
+
+.thinking-spinner {
+  width: 0.95rem;
+  height: 0.95rem;
+  border-radius: 999px;
+  border: 2px solid #bed0f3;
+  border-top-color: #2b63d9;
+  display: inline-block;
+  margin-right: 0.45rem;
+  animation: spin 0.8s linear infinite;
+  vertical-align: -0.1rem;
+}
+
+@keyframes spin {
+  to {
+    transform: rotate(360deg);
+  }
+}
+
 .bubble p {
   margin: 0;
   white-space: pre-wrap;
@@ -349,6 +462,17 @@ button:disabled {
     grid-template-columns: 1fr;
   }
 
+  .main-head {
+    flex-direction: column;
+    align-items: flex-start;
+  }
+
+  .main-head-actions {
+    width: 100%;
+    justify-content: flex-start;
+    flex-wrap: wrap;
+  }
+
   .bubble {
     max-width: 100%;
   }