Reply To: Do theme updates disrupt custom CSS added in the theme customization section?

Hello hollywoodmetal,
Thank you for using our theme SuperMag.
If you need to change the main theme any file, please do not do that. We strongly recommend to use child theme for that.
But for adding only CSS you can use theme customizer options:
Appearance=> Customize => Layout/Design Option => Custom CSS and use Custom CSS
Please never change the parent ( Main ) theme itself.