updated to dark mode

app.py

@@ -50,6 +50,7 @@ def train(data, alpha=0.0001, epochs=500, test_data=[1,2,3]):
         #title="Best Fit Line",
         xaxis_title="X",
         yaxis_title="Y",
+        template="plotly_dark"
     )
 
     fig4 = px.line(errors, template="plotly_dark")