WPF override theme style guidence

Hi, i am developing WPF project and new to xaml. i need you guidence about how to override an applied theme style. i should take 1 minute of yours. i have applied [login to view URL] style to my WPF window ([login to view URL]) and i want the TabControlItem Header to look more formal , and smaller in size. The solution to my problem posted in following pages, but i couldnt apply to my app. [login to view URL] [login to view URL]