Brings the classic NI blue and Nigel the eagle back to ni.com
It's not so much about debranding, as it is making ni.com more visually accessible. With the green theme, clickable links are almost impossible to differentiate from normal text (update Jun18: links are now underlined - more visible, but looks clunky). The choice to use a very dark green against a white background is visually fatiguing, especially when reading the forums and online documentation.
Also I missed Nigel.
This theme requires the Stylus browser plugin. After installing it, use it to create a new style, then and copy and paste the contents of ni-blue-theme.css into the style. Give it a name, save it, and that's it!