Overriding or setting all button colors in app.xaml win ui visual studio 2022 c#

[ghost]

Hello everybody.
I am new to win ui and I was used to visual studio c# designer Windows forms. Now I am attempting to program in C# for win iu 3 on visual studio Community 2022.
I have managed to override the behaviour of pointerover on buttons. I want that all my buttons (and new one in the project) to have a determined color depending on the windows theme selected previously, Light, Dark,... but the following code doesn't change any colors on the button (no style on the buttons), only the pointer over change of colors works..

(this code is in App.xaml)

<ResourceDictionary.ThemeDictionaries>







</ResourceDictionary.ThemeDictionaries>

Any suggestions?
Can I find a list of the x:keys used or defined in the dictionary ThemeDictionaries?

[ghost]

The missing code..First time at this

[ghost]

<ResourceDictionary> <ResourceDictionary.ThemeDictionaries> <ResourceDictionary x:Key="Light"> <SolidColorBrush x:Key="ButtonForegroundPointerOver" Color="Red"/> <SolidColorBrush x:Key="ButtonBackgroundPointerOver" Color="Black"/> <SolidColorBrush x:Key="ButtonBackground" Color="Black" /> <SolidColorBrush x:Key="ButtonBorderBrush" Color="DarkGray" /> <SolidColorBrush x:Key="ButtonForeground" Color="White" /> </ResourceDictionary> </ResourceDictionary.ThemeDictionaries> </ResourceDictionary>