diff --git a/src/components/AnnotationViews/AnnotationPageView.tsx b/src/components/AnnotationViews/AnnotationPageView.tsx
index 7c95428..7617f03 100644
--- a/src/components/AnnotationViews/AnnotationPageView.tsx
+++ b/src/components/AnnotationViews/AnnotationPageView.tsx
@@ -266,10 +266,14 @@ export default function AnnotationPageView({
               <div className="flex gap-3">
                 <button
                   onClick={() => setSidebarOpen(!sidebarOpen)}
-                  className="hidden md:block text-sm px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md transition-colors"
+                  className="hidden md:flex items-center justify-center w-8 h-8 bg-gray-100 hover:bg-gray-200 text-gray-600 rounded-md transition-colors"
                   title={sidebarOpen ? 'Sidebar ausblenden' : 'Sidebar anzeigen'}
                 >
-                  {sidebarOpen ? '✕' : '☰'}
+                  <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+                    <rect x="3" y="3" width="18" height="18" rx="2"/>
+                    <line x1="9" y1="3" x2="9" y2="21"/>
+                    {sidebarOpen && <rect x="3" y="3" width="6" height="18" rx="2" fill="currentColor" stroke="none"/>}
+                  </svg>
                 </button>
 
                 {Object.keys(dialectScores).length > 0 && (