Assuming you have followed the latest instructions for installing version 2.x found here: http://www.pixate.com/docs/framework/ios/latest/getting-started/
Then make sure you have the following in your AppDelegate:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//Initalize Pixate
self.window.styleMode = PXStylingNormal;
//Dynamically modify the Pixate stylesheet while the Simulator is running
#ifdef DEBUG
[Pixate styleSheetFromFilePath:@"/Users/YourHomeFolder/Path/To/default.css" withOrigin:PXStylesheetOriginApplication];
Pixate.currentApplicationStylesheet.monitorChanges = YES;
#endif
}
Hopefully that helps.