Update app.py

app.py

@@ -43,7 +43,7 @@ app.layout = dbc.Container([
         ])
     ], className="my-3"),
     dbc.Button("Split PDF", id='split-button', color="primary", className="mt-3", disabled=True),
-    dcc.Progress(id='progress-bar', className="my-3"),
+    dbc.Progress(id='progress-bar', className="my-3"),  # Changed from dcc.Progress to dbc.Progress
     dbc.Button("Download ZIP", id='download-button', color="success", className="mt-3", disabled=True),
     dcc.Download(id="download-zip"),
 ], fluid=True)