Thie function returns the interface style for the specified key and responder objects. Interface styles are described by the NSInterfaceStyle enumerator type, which may be one of the following constants:
NSNoInterfaceStyle
NSNextStepInterfaceStyle
NSWindows95InterfaceStyle
NSMacintoshInterfaceStyle
NSInterfaceStyleForKey
NSInterfaceStyleForKey(NSString *key, NSResponder *responder)