Update app.py

app.py

@@ -126,7 +126,10 @@ def initial_greeting():
     """
     Return the initial greeting message.
     """
-    return [{"role": "assistant", "content": random.choice(GREETING_MESSAGES)}]
+    return [
+        {"role": "system","content": "You are AstroSage, an intelligent AI assistant specializing in astronomy, astrophysics, and cosmology. Provide accurate, scientific information while making complex concepts accessible. You're enthusiastic about space exploration and maintain a sense of wonder about the cosmos. Start by introducing yourself."},
+        {"role": "assistant", "content": random.choice(GREETING_MESSAGES)}
+    ]
 
 
 # Custom CSS for a space theme