Add CSS for better rendering in print media type
Add CSS for better rendering in print media type

Currently, the rendered Markdown looks fine on screen, but does not
print well: the "back to top" link leaves a white box on the page that
overlays some of the text, and some of the text on the right margin is
cut off.

This commit tweaks the CSS (conditional on a print media type, so that
the on-screen rendering is not changed) to reset some of the properties.
With this change, the output looks much better in print.

yaniswang/markdownReader,samb0t/markdownReader