Nest all styles under #coverage

I've a few apps using this tool.  I'm unable to `component build --dev`,
as *all* my my apps' styles are broken.  Nesting all rules under
`#coverage` makes the styles play nicely with one another.

I also ported the css to stylus, because css sucks.
typo
Merge pull request #4 from stephenmathieson/nest-styles

Nest all styles under #coverage