With Creative Exchange styles can be edited in Components or in Page <body> tag.
Components works fine out of the box. New styles are added to Sitecore and assigned to components after import as expected.
Page body is not so easy. I added style to the page, but nothing was changed in Sitecore after importing package with that style. My changes are just ignored.
What should I do to import custom style added to <body> tag in SXA?
I am using SXA v1.1
Styles from <body> tag added to Sitecore Body Css Style page field after import. That field is defined by its ID in SXA code:
public static readonly ID BodyCssClass = new ID("{D4952280-2D7D-4BF4-A99A-EA36DAD0F0A7}");
Body Css Style field belongs to /sitecore/templates/Foundation/Experience Accelerator/Theming/_Styleable template.
The problem is, SXA pages are not inherited from that template after site is scaffolded.
To fix that, you need to open Page template for your tenant - /sitecore/templates/Project/My Tenant/Page and add _Styleable to Base templates.
After that is done, reimport Creative Exchange package and you style will appear in Body Css Style field.