[Documentation Issue] Low contrast text is hard to read.

[SurferJeffAtGoogle]

Page Name: _modules/gcloud/pubsub/topic
Release: 0.6.0

A lot of the text is dark gray on top of a light gray background. The low contrast makes it hard to read. Black and white would be easier to read.

[dhermes]

Closing this since CSS will be part of shared docs.

/cc @jgeewax