Styles in head?

[JoJk0]

I'm making a component library for my company and I'm having issues applying styles.
The ones defined in Histoire's setup file are only loaded once the component page is loaded.
Is there any way to apply styles as soon as Histoire gets opened (without stories)?
Also, styles I already have in setup are bleeding to the rest of Histoire. It would normally be fine but they get applied later and I have custom font sizes applied so there is unpleasant jump of the UI once some component story gets opened.

Particularly I need to style introduction page written in markdown so it has custom heading font and colours.
Also, is there any way to make intro page open by default while going into Histoire?

Thanks