Описание тега wpf-style
Styles are a WPF mechanism to change the appearance and behaviour of WPF controls by modifing properties and attaching event handlers from a central point.
WPF Style as a convenient way to apply a set of property values to multiple FrameworkElements (via Setters, or conditionally via Triggers).
Related styles for different FrameworkElement can be packaged together as a theme.
References: