R67 A1-A6：官网风格前端 UI 刷新

client/src/layouts/AppShellLayout.tsx

@@ -20,13 +20,14 @@ export function AppShellLayout() {
   }, [location.pathname]);
 
   return (
-    <div className="flex min-h-screen bg-[var(--color-bg-canvas)]">
+    <div className="relative flex min-h-screen overflow-hidden bg-[var(--color-bg-canvas)]">
+      <div className="pointer-events-none fixed inset-0 -z-10 bg-[radial-gradient(circle_at_12%_8%,rgba(0,57,138,0.10),transparent_28rem),radial-gradient(circle_at_90%_12%,rgba(19,168,184,0.12),transparent_32rem)]" />
       <Sidebar />
 
       <main className="flex min-w-0 flex-1 flex-col lg:ml-72">
         <Topbar />
 
-        <div className={`flex-1 px-4 py-6 sm:px-8 sm:py-8 ${isMobileRoute ? "pb-24 md:pb-8" : ""}`}>
+        <div className={`flex-1 px-4 py-5 sm:px-7 sm:py-7 lg:px-8 ${isMobileRoute ? "pb-24 md:pb-8" : ""}`}>
           <div className="layout-container max-w-none">
             <ErrorBoundary>
               <Outlet />