Now that we have this helper, we no longer need these stylesheets to
include a `body.controller-action` wrapper to scope all the styles!
Someday we should convert more of our stylesheets to this format,
instead of slamming them all into `application.sass` like we do now.
Ah, well!
Got the icon and background style from Neopets.com! I didn't quite copy
the whole button style, both because getting it to play nice with our
existing styles didn't *immediately* work, but also because I think
this works out as a really good compromise between our two styles
anyway!