try theme default

app.py

@@ -200,7 +200,7 @@ def click_button(session):
 
 
 # Gradio Interface
-with gr.Blocks(mode="light") as demo:
+with gr.Blocks(theme=gr.themes.Default()) as demo:
     session = gr.State({"username": None, "counter": 0})  # Manage session state
     # Login Section
     login_block = gr.Column(visible=True)