Update app.py

app.py

@@ -28,6 +28,7 @@ demo = gr.Interface(
     fn=generate_caption,
     inputs=[image_input, max_length_slider],
     outputs=caption_output,
+    theme="gradio/monochrome",
     title="Stable Diffusion Portrait Captioner",
     theme="default",
     allow_flagging="never"