Styling simplifications for shadows on content-wrapper and main nav
*.jqueryui.com, *.qunitjs.com, sizzlejs.com: Lighten header instead of darkening it against dark background.
learn.jquery.com: Darken header more than other sites
Upgrade Modernizr to custom 2.6.2 build. Prevents IE from matching on webkit-only media queries

http://modernizr.com/download/#-boxshadow-multiplebgs-cssgradients-shiv-mq-cssclasses-teststyles-testprop-testallprops-prefixes-domprefixes
*.jqueryui.com: Fix typo in image path for high-resolution jQuery UI logo
Provide minimal border implementation to make header stand out against background in OldIE