Update app.py

app.py

@@ -309,6 +309,8 @@ Numerous Readability Manipulation
 - Use simple and direct sentence structures. 
 - Avoid jargon; if technical terms are necessary, explain them clearly in simple language. 
 - Minimize figurative language, idioms, and expressions whose meanings are not directly inferable. 
+- Reduce average sentence length without making all sentences the same length.
+- Introduce natural variation in sentence length to maintain rhythm and avoid mechanical patterns.
   
 Qualitative Readability Control 
 ・Content preservation