diff --git a/dashboard/src/components/AppHeader.vue b/dashboard/src/components/AppHeader.vue
index 928025b..8e60ba0 100644
--- a/dashboard/src/components/AppHeader.vue
+++ b/dashboard/src/components/AppHeader.vue
@@ -18,49 +18,11 @@
     </nav>
     
     <div class="header-right">
-      <button class="header-btn" @click="toggleTheme" :title="isDark ? '切换到浅色模式' : '切换到暗色模式'">
-        <svg v-if="!isDark" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
-          <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"></path>
-        </svg>
-        <svg v-else width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
-          <circle cx="12" cy="12" r="5"></circle>
-          <line x1="12" y1="1" x2="12" y2="3"></line>
-          <line x1="12" y1="21" x2="12" y2="23"></line>
-          <line x1="4.22" y1="4.22" x2="5.64" y2="5.64"></line>
-          <line x1="18.36" y1="18.36" x2="19.78" y2="19.78"></line>
-          <line x1="1" y1="12" x2="3" y2="12"></line>
-          <line x1="21" y1="12" x2="23" y2="12"></line>
-          <line x1="4.22" y1="19.78" x2="5.64" y2="18.36"></line>
-          <line x1="18.36" y1="5.64" x2="19.78" y2="4.22"></line>
-        </svg>
-      </button>
     </div>
   </header>
 </template>
 
 <script setup>
-import { ref, onMounted } from 'vue'
-
-const isDark = ref(localStorage.getItem('theme') === 'dark')
-
-const toggleTheme = () => {
-  isDark.value = !isDark.value
-  if (isDark.value) {
-    document.documentElement.setAttribute('data-theme', 'dark')
-    localStorage.setItem('theme', 'dark')
-  } else {
-    document.documentElement.removeAttribute('data-theme')
-    localStorage.setItem('theme', 'light')
-  }
-}
-
-onMounted(() => {
-  if (localStorage.getItem('theme') === 'dark') {
-    document.documentElement.setAttribute('data-theme', 'dark')
-    isDark.value = true
-  }
-})
-
 const navItems = [
   { 
     path: '/', 
@@ -163,24 +125,6 @@ const navItems = [
   margin-left: auto;
 }
 
-.header-btn {
-  width: 32px;
-  height: 32px;
-  border-radius: 6px;
-  background: var(--bg-secondary);
-  border: 1px solid var(--border-light);
-  cursor: pointer;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  color: var(--text-secondary);
-  transition: all 0.2s;
-}
-.header-btn:hover {
-  border-color: var(--accent-primary);
-  color: var(--accent-primary);
-}
-
 @media (max-width: 768px) {
   .brand-text {
     display: none;
diff --git a/dashboard/src/main.js b/dashboard/src/main.js
index a1d4e20..e4c52c6 100644
--- a/dashboard/src/main.js
+++ b/dashboard/src/main.js
@@ -4,6 +4,11 @@ import App from './App.vue'
 import router from './router'
 import { pinia } from './utils'
 
+// 初始化夜间模式
+if (localStorage.getItem('theme') === 'dark') {
+  document.documentElement.setAttribute('data-theme', 'dark')
+}
+
 createApp(App)
   .use(router)
   .use(pinia)
diff --git a/dashboard/src/style.css b/dashboard/src/style.css
index 595e700..e83f74d 100644
--- a/dashboard/src/style.css
+++ b/dashboard/src/style.css
@@ -257,12 +257,26 @@ body {
 }
 
 .md-content blockquote {
-  border-left: 3px solid var(--border-medium);
+  border-left: 3px solid var(--text-tertiary);
   padding-left: 12px;
   margin: 0.5em 0;
   color: var(--text-secondary);
 }
 
+[data-theme="dark"] .md-content blockquote {
+  border-left-color: var(--text-secondary);
+}
+
+.md-content hr {
+  border: none;
+  border-top: 1px solid var(--border-light);
+  margin: 1em 0;
+}
+
+[data-theme="dark"] .md-content hr {
+  border-top-color: rgba(255, 255, 255, 0.2);
+}
+
 .md-content ul,
 .md-content ol {
   padding-left: 20px;
@@ -555,6 +569,33 @@ body {
   box-shadow: 0 0 0 3px var(--accent-primary-light), inset 0 1px 2px rgba(0, 0, 0, 0.2);
 }
 
+/* ============ Select Dropdown Arrow ============ */
+select {
+  appearance: none !important;
+  -webkit-appearance: none !important;
+  -moz-appearance: none !important;
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E") !important;
+  background-repeat: no-repeat !important;
+  background-position: right 10px center !important;
+  padding-right: 32px !important;
+  cursor: pointer;
+}
+
+/* 展开时箭头向上 */
+select:focus,
+select[aria-expanded="true"] {
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='18 15 12 9 6 15'%3E%3C/polyline%3E%3C/svg%3E") !important;
+}
+
+[data-theme="dark"] select {
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23a0a0a0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E") !important;
+}
+
+[data-theme="dark"] select:focus,
+[data-theme="dark"] select[aria-expanded="true"] {
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23a0a0a0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='18 15 12 9 6 15'%3E%3C/polyline%3E%3C/svg%3E") !important;
+}
+
 .page-grid {
   display: grid;
   grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
diff --git a/dashboard/src/views/ConversationsView.vue b/dashboard/src/views/ConversationsView.vue
index 2d29fa6..ffdb8db 100644
--- a/dashboard/src/views/ConversationsView.vue
+++ b/dashboard/src/views/ConversationsView.vue
@@ -105,8 +105,12 @@
               class="chat-input" 
               :disabled="sending"
             />
-            <button @click="sendMessage" class="btn-send" :disabled="sending || !newMessage.trim()">
-              {{ sending ? '发送中...' : '发送' }}
+            <button @click="sendMessage" class="btn-send" :disabled="sending || !newMessage.trim()" :title="sending ? '发送中...' : '发送'">
+              <span v-if="sending">...</span>
+              <svg v-else viewBox="0 0 24 24" width="18" height="18" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+                <line x1="22" y1="2" x2="11" y2="13"></line>
+                <polygon points="22 2 15 22 11 13 2 9 22 2"></polygon>
+              </svg>
             </button>
           </div>
         </div>
@@ -527,9 +531,28 @@ onUnmounted(() => {
   animation: pulse 1.5s ease-in-out infinite;
 }
 .conv-item-actions { display: flex; gap: 0.25rem; opacity: 1; }
-.btn-icon { padding: 0.2rem; background: transparent; border: none; cursor: pointer; font-size: 0.75rem; opacity: 0.6; transition: opacity 0.15s; }
-.btn-icon:hover { opacity: 1; }
+.btn-icon {
+  background: transparent;
+  border: none;
+  cursor: pointer;
+  padding: 4px;
+  border-radius: 4px;
+  color: var(--text-secondary);
+  transition: all 0.15s;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+.btn-icon:hover {
+  background: var(--bg-hover);
+  color: var(--accent-primary);
+}
+.btn-icon svg {
+  width: 14px;
+  height: 14px;
+}
 .btn-delete-icon { color: var(--danger-color); }
+.btn-delete-icon:hover { color: var(--danger-color); }
 
 /* 侧边栏分页 */
 .sidebar-pagination { display: flex; justify-content: center; align-items: center; gap: 0.75rem; padding: 0.75rem; border-top: 1px solid var(--border-light); font-size: 0.8rem; color: var(--text-secondary); }
@@ -575,8 +598,9 @@ onUnmounted(() => {
 .chat-input-area { padding: 1rem; border-top: 1px solid var(--border-light); display: flex; gap: 0.75rem; }
 .chat-input { flex: 1; padding: 0.65rem 0.9rem; border: 1px solid var(--border-input); border-radius: 8px; background: var(--bg-input); color: var(--text-primary); font-size: 0.9rem; }
 .chat-input:focus { outline: none; border-color: var(--accent-primary); }
-.btn-send { padding: 0.5rem 1rem; background: var(--accent-primary); color: white; border: none; border-radius: 8px; cursor: pointer; font-size: 0.85rem; }
-.btn-send:hover { background: var(--accent-primary-hover); }
+.btn-send { width: 40px; height: 40px; background: var(--accent-primary); color: white; border: none; border-radius: 8px; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: all 0.15s ease; }
+.btn-send:hover:not(:disabled) { background: var(--accent-primary-hover); transform: translateY(-1px); box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3); }
+.btn-send:disabled { opacity: 0.5; cursor: not-allowed; }
 
 /* 按钮样式 */
 .btn-primary { padding: 0.5rem 1rem; background: var(--accent-primary); color: white; border: none; border-radius: 6px; cursor: pointer; font-size: 0.85rem; transition: all 0.2s; }
diff --git a/dashboard/src/views/SettingsView.vue b/dashboard/src/views/SettingsView.vue
index d0aeed0..1cafb86 100644
--- a/dashboard/src/views/SettingsView.vue
+++ b/dashboard/src/views/SettingsView.vue
@@ -33,6 +33,28 @@
       </div>
     </div>
 
+    <!-- 外观设置 -->
+    <div class="settings-section">
+      <div class="section-title">
+        <span class="section-icon">🎨</span>
+        <span class="section-text">外观</span>
+      </div>
+      <div class="settings-card">
+        <div class="settings-row">
+          <div class="row-label">
+            <span class="row-title">夜间模式</span>
+            <span class="row-desc">切换深色/浅色主题</span>
+          </div>
+          <div class="row-value">
+            <label class="switch" @click.prevent="toggleTheme">
+              <input type="checkbox" v-model="isDark" />
+              <span class="slider"></span>
+            </label>
+          </div>
+        </div>
+      </div>
+    </div>
+
     <!-- 模型设置 -->
     <div class="settings-section">
       <div class="section-title">
@@ -250,6 +272,27 @@ import { useRouter } from 'vue-router'
 const router = useRouter()
 const { logout } = useAuth()
 
+// 夜间模式
+const isDark = ref(localStorage.getItem('theme') === 'dark')
+
+const toggleTheme = () => {
+  isDark.value = !isDark.value
+  if (isDark.value) {
+    document.documentElement.setAttribute('data-theme', 'dark')
+    localStorage.setItem('theme', 'dark')
+  } else {
+    document.documentElement.removeAttribute('data-theme')
+    localStorage.setItem('theme', 'light')
+  }
+}
+
+onMounted(() => {
+  if (localStorage.getItem('theme') === 'dark') {
+    document.documentElement.setAttribute('data-theme', 'dark')
+    isDark.value = true
+  }
+})
+
 const handleLogout = async () => {
   if (!confirm('确定要退出登录吗？')) return
   await logout(authAPI)
@@ -486,6 +529,7 @@ onMounted(() => {
 /* 内联输入框 */
 .inline-select, .inline-input { padding: 0.5rem 0.75rem; border: 1px solid var(--border-input); border-radius: 6px; background: var(--bg-input); color: var(--text-primary); font-size: 0.85rem; min-width: 180px; }
 .inline-input { width: 120px; }
+.inline-input { width: 120px; }
 .input-with-hint { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
 .hint-inline { font-size: 0.75rem; color: var(--text-tertiary); }
 textarea { width: 100%; padding: 0.75rem; border: 1px solid var(--border-input); border-radius: 8px; background: var(--bg-input); color: var(--text-primary); font-size: 0.85rem; resize: vertical; min-height: 80px; box-sizing: border-box; }