Hybrid projects

# Including CSS best practices for Hybrid App projects

Status: **Up For Review**

Reviewers: @kpeatt @rosshojo @jeffkamo @mobifydave @jansepar 
JIRA: https://mobify.atlassian.net/browse/GOLD-1164

## Changes
- Initialized new page in the css code styles and filled in what we currently have established as best practices.
Also, I know we did this because it was the fastest way to get app-specific changes, but I just want to make sure, is the consensus to have a separate file for different platforms as our long term solution?