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

frontend/src/components/UnifiedShareModal.tsx

@@ -96,7 +96,7 @@ export const UnifiedShareModal: React.FC<UnifiedShareModalProps> = ({
 
   return (
     <div
-      className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-xs"
+      className="fixed inset-0 !m-0 modal-overlay z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-xs"
       onClick={(e) => {
         if (e.target === e.currentTarget) onClose();
       }}