diff --git a/src/assets/main.css b/src/assets/main.css
index c347e20..fa211d2 100644
--- a/src/assets/main.css
+++ b/src/assets/main.css
@@ -11,10 +11,48 @@ body,
   padding: 0;
 }
 
+/*
+ * 背景统一绘制在 <html> 上：
+ * 根元素的背景会被绘制到整个画布（canvas）上，铺满窗口的每一个像素，
+ * 不会出现“元素高度(100vh) 与实际窗口差几个像素”导致的上下留白。
+ */
+html {
+  background-color: #eef2ff;
+  background-image:
+    radial-gradient(1200px 600px at 10% -10%, rgba(99, 102, 241, 0.28), transparent 60%),
+    radial-gradient(1000px 500px at 110% 10%, rgba(34, 211, 238, 0.28), transparent 55%),
+    linear-gradient(160deg, #eef2ff 0%, #f8fafc 45%, #eef7ff 100%);
+  background-repeat: no-repeat;
+}
+
+html.dark {
+  background-color: #0b1220;
+  background-image:
+    radial-gradient(1200px 600px at 10% -10%, rgba(99, 102, 241, 0.35), transparent 60%),
+    radial-gradient(1000px 500px at 110% 10%, rgba(14, 165, 233, 0.28), transparent 55%),
+    linear-gradient(160deg, #0b1220 0%, #0f172a 45%, #111827 100%);
+}
+
+/* 选中自定义背景图时替换为图片：等比缩放铺满，不拉伸变形 */
+html.has-bg-image {
+  background-image: var(--app-bg-image, none);
+  background-size: cover;
+  background-position: center center;
+  background-repeat: no-repeat;
+}
+
 body {
   overflow: hidden;
   font-family: 'Inter', 'HarmonyOS Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
   -webkit-font-smoothing: antialiased;
+  /* 背景交由 <html> 绘制，body 保持透明避免覆盖画布背景 */
+  background-color: transparent;
+}
+
+/* 窗口圆角固定 8px，与 Windows 11 系统默认圆角保持一致 */
+#app {
+  border-radius: 8px;
+  overflow: hidden;
 }
 
 /* 悬浮磨砂玻璃面板 */
diff --git a/src/config/backgrounds.ts b/src/config/backgrounds.ts
index ab13fb6..10a364b 100644
--- a/src/config/backgrounds.ts
+++ b/src/config/backgrounds.ts
@@ -1,6 +1,6 @@
 import bg1 from "@/assets/images/bg-1.webp"
 import bg2 from "@/assets/images/bg-2.webp"
-import bg3 from "@/assets/images/bg-3.webp"
+// import bg3 from "@/assets/images/bg-3.webp" // 暂时下架「背景三」，需要时与下方选项一并恢复
 
 /** 窗口背景图片标识 */
 export type BackgroundKey = "none" | "bg-1" | "bg-2" | "bg-3"
@@ -19,7 +19,7 @@ export const backgroundOptions: BackgroundOption[] = [
   { key: "none", label: "settings.appearance.none", url: "" },
   { key: "bg-1", label: "settings.appearance.bg1", url: bg1 },
   { key: "bg-2", label: "settings.appearance.bg2", url: bg2 },
-  { key: "bg-3", label: "settings.appearance.bg3", url: bg3 },
+  // { key: "bg-3", label: "settings.appearance.bg3", url: bg3 },
 ]
 
 export const DEFAULT_BACKGROUND: BackgroundKey = "none"
diff --git a/src/i18n/locales/en-US.json b/src/i18n/locales/en-US.json
index d3785e2..16279ba 100644
--- a/src/i18n/locales/en-US.json
+++ b/src/i18n/locales/en-US.json
@@ -22,7 +22,8 @@
     "dashboard": "Dashboard",
     "servers": "Servers",
     "tunnels": "Tunnels",
-    "download": "Download frpc"
+    "download": "Download frpc",
+    "setting": "Settings"
   },
   "system": {
     "cpu": "CPU usage",
diff --git a/src/i18n/locales/zh-CN.json b/src/i18n/locales/zh-CN.json
index bfaeec5..27fb09f 100644
--- a/src/i18n/locales/zh-CN.json
+++ b/src/i18n/locales/zh-CN.json
@@ -22,7 +22,8 @@
     "dashboard": "仪表盘",
     "servers": "服务器",
     "tunnels": "隧道列表",
-    "download": "Frpc 下载"
+    "download": "Frpc 下载",
+    "setting": "设置"
   },
   "system": {
     "cpu": "CPU 占用",
diff --git a/src/layout/Layout.vue b/src/layout/Layout.vue
index 92cb1ab..f04b3ea 100644
--- a/src/layout/Layout.vue
+++ b/src/layout/Layout.vue
@@ -1,6 +1,6 @@
 <template>
-  <!-- 应用整体：背景（渐变 / 图片） + 悬浮面板 -->
-  <div class="app-shell flex h-screen w-screen flex-col overflow-hidden" :style="shellStyle">
+  <!-- 应用整体：背景由 <html> 统一绘制，此处只负责布局 -->
+  <div class="app-shell flex h-full w-full flex-col overflow-hidden">
     <!-- 顶部自定义 TitleBar -->
     <Header @settings="goToSetting" />
 
@@ -18,46 +18,11 @@
 <script setup lang="ts">
 import Header from "./header/Header.vue"
 import Aside from "./aside/Aside.vue"
-import { useAppStore } from "@/stores/app"
 
 const router = useRouter()
-const appStore = useAppStore()
 
 /** 点击标题栏“设置”按钮 → 跳转设置页 */
 function goToSetting() {
   router.push("/setting")
 }
-
-/**
- * 选中背景图片时覆盖默认渐变背景。
- * `cover` 让图片按原始比例缩放铺满窗口，不会变形拉伸。
- */
-const shellStyle = computed(() =>
-  appStore.backgroundUrl
-    ? {
-        backgroundImage: `url('${appStore.backgroundUrl}')`,
-        backgroundSize: "cover",
-        backgroundPosition: "center",
-        backgroundRepeat: "no-repeat",
-      }
-    : {},
-)
 </script>
-
-<style scoped lang="scss">
-.app-shell {
-  background-color: #eef2ff;
-  background-image:
-    radial-gradient(1200px 600px at 10% -10%, rgba(99, 102, 241, 0.28), transparent 60%),
-    radial-gradient(1000px 500px at 110% 10%, rgba(34, 211, 238, 0.28), transparent 55%),
-    linear-gradient(160deg, #eef2ff 0%, #f8fafc 45%, #eef7ff 100%);
-}
-
-.dark .app-shell {
-  background-color: #0b1220;
-  background-image:
-    radial-gradient(1200px 600px at 10% -10%, rgba(99, 102, 241, 0.35), transparent 60%),
-    radial-gradient(1000px 500px at 110% 10%, rgba(14, 165, 233, 0.28), transparent 55%),
-    linear-gradient(160deg, #0b1220 0%, #0f172a 45%, #111827 100%);
-}
-</style>
diff --git a/src/layout/aside/Aside.vue b/src/layout/aside/Aside.vue
index eabbbcc..dfcf267 100644
--- a/src/layout/aside/Aside.vue
+++ b/src/layout/aside/Aside.vue
@@ -3,51 +3,48 @@
   <aside class="glass-panel flex w-56 shrink-0 flex-col overflow-hidden">
     <!-- 菜单区 -->
     <div class="flex-1 overflow-y-auto p-2">
-      <a-menu
-        class="aside-menu"
-        mode="inline"
-        :selected-keys="selectedKeys"
-        :items="menuItems"
-        @click="onMenuClick"
-      />
+      <a-menu class="aside-menu" mode="inline" :selected-keys="selectedKeys" :items="menuItems" @click="onMenuClick" />
     </div>
 
     <!-- 底部系统信息区（与菜单之间有间隔） -->
-    <div class="system-panel mt-2 border-t p-3">
-      <!-- CPU -->
-      <div class="mb-2">
-        <div class="mb-1 flex items-center justify-between text-xs">
-          <span class="opacity-70">{{ t("system.cpu") }}</span>
-          <span class="font-medium tabular-nums">{{ cpu }}%</span>
+    <div class="system-panel mt-2 border-t px-2 pb-2 pt-3">
+      <div class="px-1">
+        <!-- CPU -->
+        <div class="mb-2">
+          <div class="mb-1 flex items-center justify-between text-xs">
+            <span class="opacity-70">{{ t("system.cpu") }}</span>
+            <span class="font-medium tabular-nums">{{ cpu }}%</span>
+          </div>
+          <a-progress :percent="cpu" :show-info="false" :stroke-color="barColor(cpu)" size="small" />
+        </div>
+
+        <!-- 内存 -->
+        <div class="mb-3">
+          <div class="mb-1 flex items-center justify-between text-xs">
+            <span class="opacity-70">{{ t("system.memory") }}</span>
+            <span class="font-medium tabular-nums">{{ memory }}%</span>
+          </div>
+          <a-progress :percent="memory" :show-info="false" :stroke-color="barColor(memory)" size="small" />
+        </div>
+
+        <!-- 运行状态 -->
+        <div class="flex items-center gap-2 text-xs">
+          <span class="h-2 w-2 shrink-0 rounded-full" :class="statusDotClass" />
+          <span class="opacity-70">{{ t("system.status") }}</span>
+          <span class="font-medium">{{ statusText }}</span>
         </div>
-        <a-progress
-          :percent="cpu"
-          :show-info="false"
-          :stroke-color="barColor(cpu)"
-          size="small"
-        />
       </div>
 
-      <!-- 内存 -->
-      <div class="mb-3">
-        <div class="mb-1 flex items-center justify-between text-xs">
-          <span class="opacity-70">{{ t("system.memory") }}</span>
-          <span class="font-medium tabular-nums">{{ memory }}%</span>
-        </div>
-        <a-progress
-          :percent="memory"
-          :show-info="false"
-          :stroke-color="barColor(memory)"
-          size="small"
+      <!-- 设置入口（位于运行状态下方） -->
+      <div class="system-divider mt-3 border-t pt-2">
+        <a-menu
+          class="aside-menu"
+          mode="inline"
+          :selected-keys="settingSelectedKeys"
+          :items="settingItems"
+          @click="onMenuClick"
         />
       </div>
-
-      <!-- 运行状态 -->
-      <div class="flex items-center gap-2 text-xs">
-        <span class="h-2 w-2 shrink-0 rounded-full" :class="statusDotClass" />
-        <span class="opacity-70">{{ t("system.status") }}</span>
-        <span class="font-medium">{{ statusText }}</span>
-      </div>
     </div>
   </aside>
 </template>
@@ -59,6 +56,7 @@ import {
   CloudServerOutlined,
   DashboardOutlined,
   DownloadOutlined,
+  SettingOutlined,
 } from "@ant-design/icons-vue"
 import { useI18n } from "vue-i18n"
 import type { MenuProps } from "ant-design-vue"
@@ -74,6 +72,9 @@ const { cpu, memory } = useSystemStats()
 
 const selectedKeys = computed(() => [route.path])
 
+/** 设置项在运行状态下方独立渲染，子路由（如 /setting/appearance）同样高亮 */
+const settingSelectedKeys = computed(() => (route.path.startsWith("/setting") ? ["/setting"] : []))
+
 const menuItems = computed<MenuProps["items"]>(() => [
   { key: "/dashboard", icon: () => h(DashboardOutlined), label: t("menu.dashboard") },
   { key: "/servers", icon: () => h(CloudServerOutlined), label: t("menu.servers") },
@@ -81,6 +82,10 @@ const menuItems = computed<MenuProps["items"]>(() => [
   { key: "/download", icon: () => h(DownloadOutlined), label: t("menu.download") },
 ])
 
+const settingItems = computed<MenuProps["items"]>(() => [
+  { key: "/setting", icon: () => h(SettingOutlined), label: t("menu.setting") },
+])
+
 const onMenuClick: MenuProps["onClick"] = ({ key }) => {
   router.push(String(key))
 }
@@ -124,6 +129,15 @@ const statusText = computed(() => {
   border-color: rgba(255, 255, 255, 0.08);
 }
 
+/* 系统信息与设置入口之间的分隔线 */
+.system-divider {
+  border-color: rgba(15, 23, 42, 0.06);
+}
+
+.dark .system-divider {
+  border-color: rgba(255, 255, 255, 0.06);
+}
+
 /* 让 Antd 菜单透明化，融入磨砂玻璃面板 */
 .aside-menu {
   background: transparent;
diff --git a/src/stores/app.ts b/src/stores/app.ts
index 38731ba..156efdc 100644
--- a/src/stores/app.ts
+++ b/src/stores/app.ts
@@ -32,6 +32,19 @@ export const useAppStore = defineStore("app", () => {
   const background = useStorage<BackgroundKey>("frpilot:background", DEFAULT_BACKGROUND)
   const backgroundUrl = computed(() => getBackgroundUrl(background.value))
 
+  // 把背景图同步到 <html>（整窗背景，避免元素高度误差造成的上下留白）
+  watchEffect(() => {
+    const root = document.documentElement
+    const url = backgroundUrl.value
+    if (url) {
+      root.style.setProperty("--app-bg-image", `url('${url}')`)
+      root.classList.add("has-bg-image")
+    } else {
+      root.classList.remove("has-bg-image")
+      root.style.removeProperty("--app-bg-image")
+    }
+  })
+
   // Frpc 运行状态（后续由后端驱动）
   const runStatus = ref<RunStatus>("stopped")