Update app.py

app.py

@@ -93,13 +93,16 @@ def build_prompt(text: str, target_level: int, prompt_mode: str) -> str:
 
     if prompt_mode == "legacy":
         return f"""
-Rewrite the following passage so it fits about {target_flesch} Flesch Reading Ease Score
-- Extract only the portions of the text that should be read as the main body,
-excluding the title, author name, source information, chapter number, annotations, and footers.
-- When outputting, make sure sections divided by chapters, etc., are clearly distinguishable by leaving a blank line between them.
-- Preserve the original meaning faithfully. 
-- Do not add new information or remove essential information. 
-- Output only the rewritten passage. Do not include explanations. 
+Rewrite the following text to achieve a Flesch Readability Score of {target_flesch}.
+
+Requirements:
+- Extract only the main text, excluding titles, author names, source information, chapter numbers, annotations, footers, etc.
+- Clearly separate sections such as chapters by inserting blank lines between them.
+- Maintain the original meaning faithfully; do not add or remove important information.
+- Rewrite into clear, modern, and natural English suitable for learners at the target level.
+  Avoid archaic expressions, inverted syntax, and literary expressions typical of old picture books.
+  Use simple, modern sentence structures and word order.
+- Output only the rewritten text. Do not include explanatory notes or other additional text.
 {text}
 """