Category background images do not scale good for mobile

[Pad_Pors]

here are two samples:

https://padpors.com/c/PP-Porch/Library

https://padpors.com/c/PP-Porch

even in safe-mode and when the themes are deactivated, you can see the background image in a topic page. e.g. of safe-mode activated page:

https://padpors.com/t/آیا-تا-حالا-تجربه-ای-از-کار-داوطلبانه-بین-المللی-توی-حوزه-کامپیوتر-داشتین؟/10482/?safe_mode=no_custom%2Cno_plugins%2Conly_official