Update app.py

app.py

@@ -1,5 +1,16 @@
 import streamlit as st
+# Set the configuration for the dark theme
+def set_theme():
+    st.set_page_config(
+        page_title='PVT Gas',  # Title of your app
+        layout='wide',               # Can be "wide" or "centered"
+    )
 
+    # Use Streamlit's theming options to set the default to dark
+    st.write('<style>body { color: white; background-color: #0E1117; }</style>', unsafe_allow_html=True)
+
+# Call the function to set the theme
+set_theme()
 ss = st.session_state
 
 GC_NAMES = ['Hydrogen sulphide',