diff --git a/apps/web/src/App.tsx b/apps/web/src/App.tsx
index 11cc3fb..508f0c3 100644
--- a/apps/web/src/App.tsx
+++ b/apps/web/src/App.tsx
@@ -50,6 +50,7 @@ import {
   deletePlatform,
   deleteTenant,
   deleteUserGroup,
+  GatewayApiError,
   getHealth,
   listFileStorageChannels,
   getFileStorageSettings,
@@ -271,7 +272,8 @@ export function App() {
           loadedDataKeysRef.current.add('modelRateLimits');
           loadedDataKeysRef.current.add('platforms');
         })
-        .catch(() => {
+        .catch((err) => {
+          if (handleAuthExpired(err, token)) return;
           loadedDataKeysRef.current.delete('modelRateLimits');
           loadedDataKeysRef.current.delete('platforms');
         });
@@ -370,6 +372,7 @@ export function App() {
       requestKeys.forEach((key) => loadedDataKeysRef.current.add(key));
       setState('ready');
     } catch (err) {
+      if (handleAuthExpired(err, nextToken)) return;
       setState('error');
       setError(err instanceof Error ? err.message : '加载失败');
     } finally {
@@ -925,7 +928,7 @@ export function App() {
     }
   }
 
-  function signOut() {
+  function resetAuthenticatedSession() {
     persistAccessToken('');
     setToken('');
     loadedDataKeysRef.current = new Set(health ? ['health'] : []);
@@ -962,6 +965,19 @@ export function App() {
     setWalletTransactionTotal(0);
     setWorkspaceTransactionQuery(defaultWorkspaceTransactionQuery());
     setCoreMessage('');
+  }
+
+  function handleAuthExpired(err: unknown, failedToken: string) {
+    if (!failedToken || !(err instanceof GatewayApiError) || err.details.status !== 401) return false;
+    resetAuthenticatedSession();
+    setError('');
+    setAuthMode('login');
+    navigatePath(pathForWorkspaceSection('overview'));
+    return true;
+  }
+
+  function signOut() {
+    resetAuthenticatedSession();
     navigatePath('/');
   }
 
diff --git a/apps/web/src/styles/playground.css b/apps/web/src/styles/playground.css
index 42a28fc..7a2d1ce 100644
--- a/apps/web/src/styles/playground.css
+++ b/apps/web/src/styles/playground.css
@@ -753,6 +753,9 @@
 }
 
 .contentShell[data-page="playground"] {
+  position: relative;
+  display: flex;
+  flex-direction: column;
   width: 100vw;
   height: 100%;
   min-height: 0;
@@ -761,6 +764,31 @@
   padding: 0;
 }
 
+.contentShell[data-page="playground"] > .notice,
+.contentShell[data-page="playground"] > .shBadge {
+  position: absolute;
+  z-index: 30;
+  flex: 0 0 auto;
+  box-shadow: 0 12px 34px rgba(154, 52, 18, 0.12);
+}
+
+.contentShell[data-page="playground"] > .shBadge {
+  top: 10px;
+  left: 12px;
+}
+
+.contentShell[data-page="playground"] > .notice {
+  top: 38px;
+  left: 12px;
+  width: min(680px, calc(100% - 24px));
+  margin: 0;
+}
+
+.contentShell[data-page="playground"] > .playgroundPage {
+  flex: 1 1 auto;
+  height: auto;
+}
+
 .playgroundPage {
   --playground-content-width: 960px;
   display: grid;
@@ -1396,7 +1424,7 @@
   position: sticky;
   bottom: 0;
   margin: auto auto 0;
-  padding-top: 18px;
+  padding: 18px 0 24px;
   background: linear-gradient(180deg, rgba(250, 250, 250, 0), var(--surface-subtle) 40%);
 }
 
@@ -2223,7 +2251,7 @@
 }
 
 .mediaComposerDock {
-  padding: 16px 40px 28px;
+  padding: 16px 40px 24px;
   background: linear-gradient(180deg, rgba(250, 250, 250, 0), var(--surface-subtle) 26%);
 }
 
@@ -2388,7 +2416,11 @@
   }
 
   .mediaComposerDock {
-    padding: 12px 18px 18px;
+    padding: 12px 18px 20px;
+  }
+
+  .assistantComposerDock {
+    padding-bottom: 20px;
   }
 
   .composerQuickPrompts {