Update app.py

app.py

@@ -18,7 +18,7 @@ if not hf_api_key:
     raise ValueError("HF_API_KEY not set in environment variables")
 
 API_URL = "https://api-inference.huggingface.co/models/stabilityai/stable-diffusion-xl-base-1.0"
-headers = {"Authorization": f"Bearer {huggingface_api_key}"}
+headers = {"Authorization": f"Bearer {hf_api_key}"}
 
 #------------------------------------------------------------------------
 # Configurations