[OFFAPPS-95] Change app style to meet new Creative guidelines

:art:

Change app style to meet new Creative guidelines.

JIRA: https://zendesk.atlassian.net/browse/OFFAPPS-95

![screen shot 2013-10-04 at 10 54 42](https://f.cloud.github.com/assets/172804/1268264/1f905e6e-2cdb-11e3-8d12-74a466439e1b.png)


/cc @maximeprades