Update app.py

app.py

@@ -38,12 +38,12 @@ examples = [
 
 
 css="""
-body {
+#body {
     font-family: Arial, sans-serif;
     background-color: #f2f2f2;
 }
 
-col-container {
+#gr-col-container {
     margin: 0 auto;
     max-width: 520px;
     padding: 20px;