Update app.py

app.py

@@ -16,7 +16,8 @@ st.markdown("""
         }
         .stApp {
             background-image: url('https://i.pinimg.com/736x/9c/7b/33/9c7b33bca7b7dfd8c22daa0fd3d12b05.jpg');
-            background-color: black;
+            background-size: cover;
+            background-position: center;
             padding: 20px;
             border-radius: 10px;
             box-shadow: 2px 2px 10px rgba(0, 0, 0, 0.1);