PenciDesign Supporter replied
Hi,
1. The uninstalled demo progress will delete all the data of this demo imported to your site before, including pages, posts, menus, widgets, ... even when you've edited.
2. If your site already contains the data, you should import the customized style only,
3. If you've imported the full demo content data and planning to change this in the future, please use a Duplicate plugin here to create a clone page/post before editing to avoid data loss when uninstalling demo data.
Regards,
PenciDesign.