Creating a new dependent skin
When you create a new skin, you can add a parent skin. The new skin becomes dependent on the parent and inherits the parent's formats and mixins. If the parent skin is changed, those changes are inherited by the dependent skin.
In the Label field on the Create Skin screen, enter a name for the skin.
In the Additional creation options area, select the Inherit component formats and mixins from an existing skin check box and use the corresponding field to select the skin that you want to inherit from.
Finish the skin creation as you would any normal skin. The newly created skin now inherits formats from the specified parent skin.