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.