Porting Ionic1 theme to v3

Hi everyone,
I have got a Ionic v1 hybrid app which uses the old theming system, where a lot of .sass files are grouped together inside one single directory and I would like to port the theme to Ionic v3, where each view has got a separate .sass file for customisation. It is a template from the marketplace so I am not totally aware of the content of each file, yet the naming reflects where each styling file belongs to (for instance auth.login or auth.common or chat.detail)

Unfortunately, due to advanced customisation needs, each file relies on a lot of misc/utils/common dependencies and can’t be simply copy-pasted to the associated view without breaking the app.
How can I do it?

Thank you