Update app.py

app.py

@@ -163,12 +163,14 @@ def create_arena_interface():
         css="""
             .invisible-textbox {
                 position: fixed;
-                opacity: 0;
+                opacity: 0.1;
                 pointer-events: auto;
-                width: 0;
-                height: 0;
-                padding: 0;
-                margin: 0;
+                width: 100px;
+                height: 20px;
+                padding: 5px;
+                margin: 5px;
+                background: #f0f0f0;
+                border: 1px solid #ddd;
             }
         """,
     ) as demo: