fix plot

app.py

@@ -503,8 +503,8 @@ elif selected_model == 'Cas12':
             ))
 
         # Prediction visualization
-        for index, row in df.iterrows():  # Use iterrows for safe access
-            midpoint = (row['Start_Pos'] + row['End_Pos']) / 2
+        for index, row in df.iterrows():  # Iterate over DataFrame rows safely
+            midpoint = (row['Start_Pos'] + row['End_Pos']) / 2  # Ensure columns are correctly referenced
             fig.add_trace(go.Scatter(
                 x=[midpoint],
                 y=[1],