text: Title: named styles
  Body: The idea is to provide something a bit like [bootstrap's](https://getbootstrap.com/docs/4.0/components/buttons/) "primary", "secondary", "success" etc. to customise components without resorting the the sledge hammer of CSS.
  
  I think we have:
  * `primary` - default
  * `secondary` - for "not the main thing to do"
  * `warning` - for "this does bad/irreversible" stuff
  
  That should be enough for now.