# Apply themes with App.xaml
`App.xaml`
```xml
```
# Change themes by ThemeManager
Change by `ThemeManager`
```c#
ThemeManager.CurrentTheme = ColorThemes.DarkBlue;
```
# Change themes by ResourceDictionary
As default we use Classic theme.
You also can change theme by adding resource dictionary after generic.xaml. Use one of them:
```xml
```
## NOTES
You can use custom window style named `BrightSharpWindowStyle`.
Also defined additional useful styles and extensions. For more info see Demo source code.