Update app.py

app.py

@@ -89,7 +89,7 @@ def main():
                 color: white; /* Font color */
             }
             .user-bubble {
-                background-color: #1f1f1f; /* Darker background color */
+                background-color: #007bff; /* Blue color for user */
                 align-self: flex-end;
                 border-radius: 10px;
                 padding: 8px;