You can define a style inline in the XAML for a control, or as a reusable resource.
Defining styles as a reusable resource
Style definition locations
An individual page’s XAML file (will override a same named resource in App.xaml)
Will override a same named resource in App.xaml if present.
In the App.xaml file
In a separate resource dictionary XAML file
Can be shared across apps, and more than one resource dictionary can be merged in a single app).
Scope is determined by where the resource dictionary is referenced.
String that specifies a FrameworkElement type to apply the style to.
Must specify a FrameworkElement-derived type that’s defined by the Windows Runtime or a custom type that’s available in a referenced assembly.
If you try to apply a style to a control and the control’s type doesn’t match the TargetType attribute of the style you’re trying to apply, an exception occurs.
A collection of one or more Setter elements. Each requires a Property and a Value.
If a style contains the x:Key attribute, you can only apply it to a control by setting the Style property of the control to the keyed style. A style without an x:Key attribute is automatically applied to every control of its target type, that doesn’t otherwise have an explicit style setting.
Inheriting from other styles
Use the BasedOn property