Unclear description of admin_pages_only option

[hughbris]

This description confuses me, could you explain it more clearly please?

admin_pages_only: true|false toggles if admin should only process shortcodes for Grav pages

Is this related to previewing pages or something? Does it relate to any other settings?

Also, what is are css option(s)? It's not described in the README.

Cheers