Update app.py

app.py

@@ -107,7 +107,9 @@ if add_solid:
 
         solid_info_list.append((solid_name, conc_value, conc_unit, mass_mg, mass_g))
 
-file_name = f"{preparation} {nowtime}"
+safe_name = preparation.replace(" ", "_")
+file_name = f"{safe_name}_{now.strftime('%Y-%m-%d_%H-%M-%S')}"
+
 
 # إعداد تقرير HTML
 report_html = f"""