At run time, both the target
theme and its base theme must be available. Each custom theme contains only information
about how it differs from its base theme. The base theme is deployed simultaneously
with the custom theme; both themes must be available to the consuming applications.
If you have additional layers of nesting (for example, a custom theme that depends
on another custom theme that in turn depends on a base theme), then all dependent
themes must be available. If you deploy a theme, whose base theme is not deployed,
the application automatically deploys the base theme. You cannot deploy a theme for
only a particular application or for only a particular set of users. All deployed
themes are available to all eligible applications and to all users.