extend shade area

Extend Shade Area
  
Status: **Opened for visibility**
 
Reviewers: @kpeatt @scalvert
  
## Changes
- Extending the default shade area so we won't see uncovered page scrolling behind at the edge of the viewport on some older android devices
  
## How to test-drive this PR
- Run grunt test

I'd make this -10 a larger number, and also make it a constant. Let's call it DEFAULT_PADDING