As mentioned, I've gone and updated the Play Classic page so there's no brown on it. In doing so, I finally found out how to blur the edges of an image so it's not pixellated. :( (the 'Feather' plugin for Paint.NET)
The selectors for the AoG 'Updated' text on the homepage have been updated so it looks the same in both Chrome and Firefox.
The menubar above the game applet has been given some blueness so that there's blue on every page on the RS website. The advert background on this page has also been made blue. While doing this, I found a few px of wasted space that have now been recovered and can now be used to make the game window even bigger when in resizeable mode.
If you find the blue above the game window too distracting after playing with it for a few hours, please shout and I'll see what can be done!