Fix mobile website initial width

[vgaidarji]

On mobile devices where width < 960, blog content was overlapped by panel-cover
and users were unable to see it, but were able to scroll the page.
Closes #42

In my case, I've fixed this a bit differently than proposed solution in #42. The idea is to use correct style for panel-cover when web page loads for the first time. On devices with width < 960, panel-cover is loaded with panel-cover--collapsed style by default.

Before fix:

After fix:

[joshgerdes]

Thanks for offering up a solution, but the full cover page view is preferred/desired for the initial landing page.