Trim trailing spaces and use spaces consistently in html.
Use uppercase doctype and remove type for js files (not needed in HTML5).
Move Google fonts to the html to enable parallel downloading.
Fix JSHint warnings.
css/styles.css: Remove duplicate property and overqualified element.
Specify img dimensions in index.md.
Move "border" property to styles.css.
Move commonly used style to styles.css.
styles.css: Add lines breaks.
Specify the html lang.
Move inline styles to styles.css.
Use the protocol relative url for html5shiv.
Specify favicon in the html too.
Fix validation errors.
Remove unneeded class.
Include html5shiv.js to the repo to reduce DNS lookups.
Use double quotes consistently.
robots.txt is valid now.