Introducing JSON - Mobile Display 2/3

This is my take on the json.org website.

>On-Scroll Display
Featured UX
* When you scroll two pages of your device-height, a small blue icon with an arrow point north shows at the bottom-right corner. It is a 'Back to Top' button.
* When you start scrolling a shadow appears for the header as it is a sticky feature. It will disappear after an amount of second passed. [!]This feature is under consideration: whether or not it should stay, because of the 'Back to Top' button. It may render it useless.