Update app.py

app.py

@@ -4,10 +4,21 @@ import os
 
 HF_TOKEN = os.getenv("HF_TOKEN")
 
+# ✅ Allowed subjects
+ALLOWED_TOPICS = ["biology", "physics", "chemistry", "math", "mathematics"]
+
 def respond(message, history: list[dict[str, str]]):
+    # 1️⃣ Check if the message contains allowed subjects
+    if not any(topic in message.lower() for topic in ALLOWED_TOPICS):
+        yield "❌ Sorry, I only know about Biology, Physics, Chemistry, and Maths. Please ask me about them."
+        return
+
+    # 2️⃣ Allowed topic → send to HuggingFace GPT
     client = InferenceClient(token=HF_TOKEN, model="openai/gpt-oss-20b")
 
-    messages = [{"role": "system", "content": "You are a friendly chatbot."}]
+    messages = [
+        {"role": "system", "content": "You are a friendly chatbot. You only answer questions about Biology, Physics, Chemistry, and Maths. For anything else, politely reply that you can't answer it."}
+    ]
     messages.extend(history)
     messages.append({"role": "user", "content": message})
 
@@ -38,8 +49,8 @@ custom_css = """
     background: white !important;
     padding: 12px !important;
     box-shadow: 0px 6px 25px rgba(0,0,0,0.12) !important;
-    max-width: 700px !important;   /* wider chat box */
-    margin: 0 auto !important;     /* center align */
+    max-width: 700px !important;
+    margin: 0 auto !important;
 }
 
 /* User bubble */
@@ -92,7 +103,7 @@ button:hover {
     to {opacity: 1; transform: translateY(0);}
 }
 
-/* 🔒 Hide Gradio Footer (API, Logo, Settings) only */
+/* 🔒 Hide Gradio Footer */
 footer, .svelte-1yycg3h, .builder-bar, .wrap.svelte-1ipelgc {
     display: none !important;
     visibility: hidden !important;