Our detectives are back with the following intel on this WordPress site
The site is using the Twenty Fifteen theme by the WordPress team .
We could identify 2 plugins (there might be more) - Q2W3 Fixed Widget for WordPress and WP-Recall
Our 2015 default theme is clean, blog-focused, and designed for clarity. Twenty Fifteen's simple, straightforward typography is readable on a wide variety of screen sizes, and suitable for multiple languages. We designed it using a mobile-first approach, meaning your content takes center-stage, regardless of whether your visitors arrive by smartphone, tablet, laptop, or desktop computer.