Move movement from old Bootstrap classes to PureCSS classes. Broke Pure's base CSS out into a separate local file as it looks like the colours I chose in their custom CSS generator don't work too well for primary button highlights, etc. I'll be able to pop in new definitions more easily now once I've better sample pages together.
Added a customisation omhome.css file and played around a bit more with replacing the bootstrap classes; looks like I'll have to break apart the markdown workflow they've put in place for the home page, unless I'm missing something and you can assign CSS classes to markdown content.