Modify Theme

How can i modify the Theme Basic? Like the primary color of Buttons or styles in general?

I try with this that i found in the Developer guide but show me a error!

    <Button FontSize="20"/>


<Fuse.BasicTheme.BasicTheme ColorScheme="Amber">


The first example shuld be


The second one should work, so I’m not sure what’s wrong there. Can you please tell us what error message you are getting?

Thanks! My mistake. Works great!