update css styling for chatbot

app.py

@@ -32,12 +32,13 @@ def chat(user_input):
         response += word + " "
         yield [(user_input, response)]
 
-with gr.Blocks() as demo:
+with gr.Blocks(css = """#col_container {width: 700px; margin-left: auto; margin-right: auto;}
+                #chatbot {height: 400px; overflow: auto;}""") as demo:
     gr.Markdown(f"## {TITLE}\n\n\n\n{ABSTRACT}")
+    with gr.Column(elem_id='col_container'):
+        chatbot = gr.Chatbot(elem_id='chatbot')
+        textbox = gr.Textbox(placeholder="Enter a prompt")
     
-    chatbot = gr.Chatbot()
-    textbox = gr.Textbox(placeholder="Enter a prompt")
-
-    textbox.submit(chat, textbox, chatbot)
+        textbox.submit(chat, textbox, chatbot)
 
 demo.queue(api_open=False).launch()