iPhone version: refresh icon was too large

The code contained a small CSS cascade hiccup: the CSS property that
set the background image also reset the background-size property that
appeared earlier in the CSS.

Related bug in Pivotal:
https://www.pivotaltracker.com/story/show/56421784
Template built. v1.6.2.

The new version fixes the size of the "refresh" icon in the iPhone
version.