sandboxDarkClass is not applied to variants in svelte

[Jolaxs]

hi, i have a custom css class for dark theme, and i've included it in the config file like this

histoire: {
    sandboxDarkClass: 'theme-dark',
}

This works as long as i do not use variants in my story. Is this a bug or did i miss something?
And as a side note. is there any way to specify other themes globally other than dark? Also it would be great if there was a possibility to specify a sandboxBrightClass as well in order to be less opinionated about css structure