diff --git a/client/src/App.tsx b/client/src/App.tsx
index bec56c6..31a393a 100644
--- a/client/src/App.tsx
+++ b/client/src/App.tsx
@@ -22,7 +22,7 @@ import SelectPage from "./pages/SelectPage";
 import CommunityPage from "./pages/CommunityPage";
 import { AIDrawerProvider } from "./contexts/AIDrawerContext";
 import DesktopAIShell from "./components/DesktopAIShell";
-import { appShellColumnClass, appShellGutterClass } from "./lib/appShell";
+import { appShellColumnClass, appShellOuterClass } from "./lib/appShell";
 
 const EQPage = lazy(() => import("./pages/EQPage"));
 const AIPage = lazy(() => import("./pages/AIPage"));
@@ -75,10 +75,8 @@ function App() {
             <Toaster />
             <Router hook={useHashLocation}>
               <AIDrawerProvider>
-                <div
-                  className={`min-h-dvh bg-[#0d1117] flex justify-center ${appShellGutterClass}`}
-                >
-                  <div className={`min-h-dvh ${appShellColumnClass}`}>
+                <div className={appShellOuterClass}>
+                  <div className={appShellColumnClass}>
                     <DesktopAIShell>
                       <AppRouter />
                     </DesktopAIShell>
diff --git a/client/src/components/BottomNav.tsx b/client/src/components/BottomNav.tsx
index d5b57e2..623bf1a 100644
--- a/client/src/components/BottomNav.tsx
+++ b/client/src/components/BottomNav.tsx
@@ -22,7 +22,7 @@ import {
 } from "lucide-react";
 import { Link, useLocation } from "wouter";
 import { useMemo } from "react";
-import { appShellColumnClass, appShellGutterClass } from "@/lib/appShell";
+import { bottomNavInnerClass, bottomNavOuterClass } from "@/lib/appShell";
 
 type BottomNavLocale = NonNullable<(typeof localeZh)["bottomNav"]>;
 
@@ -57,10 +57,10 @@ export default function BottomNav() {
 
   return (
     <nav
-      className={`fixed inset-x-0 bottom-0 z-50 flex justify-center pointer-events-none ${appShellGutterClass}`}
+      className={bottomNavOuterClass}
     >
       <div
-        className={`pointer-events-auto ${appShellColumnClass}`}
+        className={bottomNavInnerClass}
         style={{
           background: "rgba(10, 10, 12, 0.96)",
           backdropFilter: "blur(40px) saturate(200%)",
diff --git a/client/src/index.css b/client/src/index.css
index d35637f..c838703 100644
--- a/client/src/index.css
+++ b/client/src/index.css
@@ -119,6 +119,8 @@
   html,
   body,
   #root {
+    width: 100%;
+    max-width: 100%;
     min-height: 100%;
   }
 
@@ -176,6 +178,61 @@
     min-height: 0;
     min-width: 0;
   }
+
+  /* App shell: mobile full-bleed, desktop centered column (modern + legacy share class names). */
+  .x8-app-shell-outer {
+    min-height: 100dvh;
+    width: 100%;
+    min-width: 0;
+    display: flex;
+    justify-content: center;
+    background-color: #0d1117;
+    padding-left: 0;
+    padding-right: 0;
+  }
+
+  .x8-app-shell-column {
+    min-height: 100dvh;
+    width: 100%;
+    min-width: 0;
+    max-width: none;
+  }
+
+  .x8-bottom-nav-outer {
+    pointer-events: none;
+    position: fixed;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 50;
+    display: flex;
+    width: 100%;
+    min-width: 0;
+    justify-content: center;
+    padding-left: 0;
+    padding-right: 0;
+  }
+
+  .x8-bottom-nav-inner {
+    pointer-events: auto;
+    width: 100%;
+    min-width: 0;
+    max-width: none;
+  }
+
+  @media (min-width: 1024px) {
+    .x8-app-shell-outer,
+    .x8-bottom-nav-outer {
+      padding-left: 1.5rem;
+      padding-right: 1.5rem;
+    }
+
+    .x8-app-shell-column,
+    .x8-bottom-nav-inner {
+      max-width: 1180px;
+    }
+  }
+
   @media (min-width: 640px) {
     .container {
       padding-left: 1.5rem;
diff --git a/client/src/index.legacy.css b/client/src/index.legacy.css
index 8e593d4..1d31e9a 100644
--- a/client/src/index.legacy.css
+++ b/client/src/index.legacy.css
@@ -6,9 +6,22 @@
 html,
 body,
 #root {
+  width: 100%;
+  max-width: 100%;
   height: 100%;
 }
 
+@media (max-width: 1023px) {
+  html,
+  body {
+    overflow-x: hidden;
+    overscroll-behavior-x: none;
+  }
+  #root {
+    overflow-x: hidden;
+  }
+}
+
 body {
   background: #000;
   color: #f2f2f2;
@@ -44,6 +57,62 @@ body {
 }
 
 @layer components {
+  /* App shell: mobile full-bleed, desktop centered column (plain CSS for Chrome 91). */
+  .x8-app-shell-outer {
+    min-height: 100vh;
+    min-height: -webkit-fill-available;
+    width: 100%;
+    min-width: 0;
+    display: flex;
+    justify-content: center;
+    background-color: #0d1117;
+    padding-left: 0;
+    padding-right: 0;
+  }
+
+  .x8-app-shell-column {
+    min-height: 100vh;
+    min-height: -webkit-fill-available;
+    width: 100%;
+    min-width: 0;
+    max-width: none;
+  }
+
+  .x8-bottom-nav-outer {
+    pointer-events: none;
+    position: fixed;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 50;
+    display: flex;
+    width: 100%;
+    min-width: 0;
+    justify-content: center;
+    padding-left: 0;
+    padding-right: 0;
+  }
+
+  .x8-bottom-nav-inner {
+    pointer-events: auto;
+    width: 100%;
+    min-width: 0;
+    max-width: none;
+  }
+
+  @media (min-width: 1024px) {
+    .x8-app-shell-outer,
+    .x8-bottom-nav-outer {
+      padding-left: 1.5rem;
+      padding-right: 1.5rem;
+    }
+
+    .x8-app-shell-column,
+    .x8-bottom-nav-inner {
+      max-width: 1180px;
+    }
+  }
+
   /* Match modern .cyan-slider styling (input[type=range]) for legacy build. */
   .cyan-slider {
     -webkit-appearance: none;
diff --git a/client/src/lib/appShell.ts b/client/src/lib/appShell.ts
index 26d4c67..871df2f 100644
--- a/client/src/lib/appShell.ts
+++ b/client/src/lib/appShell.ts
@@ -1,8 +1,8 @@
 /** Centered phone-style shell width (desktop / ultrawide). */
 export const APP_SHELL_MAX_PX = 1180;
 
-/** Inner column inside horizontal gutters — use with a flex/grid centering parent. */
-export const appShellColumnClass =
-  "w-full min-w-0 max-w-[min(1180px,100%)]";
-
-export const appShellGutterClass = "px-4 sm:px-6";
+/** Responsive rules live in `.x8-app-shell-*` (index.css + index.legacy.css). */
+export const appShellOuterClass = "x8-app-shell-outer";
+export const appShellColumnClass = "x8-app-shell-column";
+export const bottomNavOuterClass = "x8-bottom-nav-outer";
+export const bottomNavInnerClass = "x8-bottom-nav-inner";
diff --git a/client/src/pages/Home.tsx b/client/src/pages/Home.tsx
index 728791d..2ff15c4 100644
--- a/client/src/pages/Home.tsx
+++ b/client/src/pages/Home.tsx
@@ -135,7 +135,7 @@ function IOSToggle({ checked, onChange }: { checked: boolean; onChange: (v: bool
 
 // ── List row ──
 function ListRow({
-  icon, label, value, onClick, toggle, checked, onToggle,
+  icon, label, value, onClick, toggle, checked, onToggle, thumbnailSrc,
 }: {
   icon: React.ReactNode;
   label: string;
@@ -144,6 +144,8 @@ function ListRow({
   toggle?: boolean;
   checked?: boolean;
   onToggle?: (v: boolean) => void;
+  /** Optional small thumbnail shown between value text and chevron. */
+  thumbnailSrc?: string;
 }) {
   return (
     <div className="ios-list-row cursor-pointer" onClick={onClick}>
@@ -157,7 +159,15 @@ function ListRow({
       {toggle ? (
         <IOSToggle checked={!!checked} onChange={onToggle ?? (() => {})} />
       ) : (
-        <div className="flex items-center gap-1">
+        <div className="flex items-center gap-1.5">
+          {thumbnailSrc && (
+            <img
+              src={thumbnailSrc}
+              alt=""
+              className="w-16 h-12 rounded-[8px] object-cover flex-shrink-0"
+              style={{ border: "1px solid rgba(255,255,255,0.12)" }}
+            />
+          )}
           {value && <span className="ios-row-value">{value}</span>}
           <ChevronRight size={16} className="ios-chevron" />
         </div>
@@ -873,6 +883,7 @@ export default function Home() {
             icon={<Gauge size={16} />}
             label={homeText.vu ?? "VU表"}
             value={vuLabel}
+            thumbnailSrc={`${import.meta.env.BASE_URL}vu/vu${(ds.vu ?? 0) + 1}.png`}
             onClick={() => setLocation("/vu")}
           />
           <ListRow
diff --git a/tailwind.legacy.config.cjs b/tailwind.legacy.config.cjs
index 379ed6b..11b2ba4 100644
--- a/tailwind.legacy.config.cjs
+++ b/tailwind.legacy.config.cjs
@@ -29,5 +29,11 @@ module.exports = {
     },
   },
   plugins: [],
+  safelist: [
+    "x8-app-shell-outer",
+    "x8-app-shell-column",
+    "x8-bottom-nav-outer",
+    "x8-bottom-nav-inner",
+  ],
 };