Judging by your screenshot, you have added the custom code to the preset’s custom CSS area so your code doesn’t work globally. First of all, navigate to the global theme settings by clicking on the “To global settings” button.

https://monosnap.com/file/nxR78FVMnKbqlbFZT1tgU7x4IAeG0j

And only then navigate to the “Custom CSS” tab and paste the code to the appropriate field.

Kind Regards