Set a custom theme / customize the default light and dark theme

Questions
1

my question is two

1, how i can customize the default light and dark theme.
2, create and add another theme to the default light and dark theme. i know i can create and generate a custom style but i want to add it to the default and use it.

For Example
The name of my theme is sunset

// framework7-custome.less

@includeSunsetTheme: true;

// app.less

:root
:root.sunset,
:root .sunset {
}

and use it