Some kind of unit testing

[michaelblyons]

Because this is CSS, changes to a selector often screw up other pages. Some kind of assertion that X is a Class, X is not a Property would be nice.

[michaelblyons]

Because this is CSS, changes to a selector often screw up other pages.

The new YAML broken out by each page mitigates the regression chance by a lot, but we should still do some kind of testing for peace of mind.