Update Topbar layout by adjusting header height and removing unused admin information for a cleaner interface

src/components/layout/Topbar.tsx

@@ -10,7 +10,7 @@ import {
 
 export function Topbar() {
   return (
-    <header className="flex h-[81px] shrink-0 items-center justify-end gap-2 border-b border-border bg-background px-8">
+    <header className="flex h-16 shrink-0 items-center justify-end gap-2 border-b border-border bg-background px-8">
       <TooltipProvider>
         <Button
           variant="outline"
@@ -48,11 +48,6 @@ export function Topbar() {
           >
             A
           </div>
-          <div className="hidden text-sm md:block text-left">
-            <div className="font-medium text-foreground">管理员</div>
-            <div className="text-xs text-muted-soft">admin</div>
-          </div>
-          <ChevronDown size={14} className="hidden md:block text-muted-soft" />
         </button>
       </TooltipProvider>
     </header>