fix(ui): prevent modal overlays from inheriting margin-top from parent space-y containers

frontend/src/features/teams/GroupsView.tsx

@@ -252,7 +252,7 @@ export const GroupsView: React.FC<GroupsViewProps> = ({ currentUser, onBack }) =
       {/* Modal: Neue Gruppe erstellen */}
       {showCreateModal && (
         <div
-          className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-xs p-4 animate-in fade-in duration-150"
+          className="fixed inset-0 !m-0 modal-overlay z-50 flex items-center justify-center bg-black/60 backdrop-blur-xs p-4 animate-in fade-in duration-150"
           onClick={() => setShowCreateModal(false)}
         >
           <div