Due to popular request, and in an effort to reduce eye-strain, a dark theme for the chat rooms has been added. It features a colour palette based off of the dark variant of the Gruvbox code editor theme, which I can attest to making staring at text for long periods much less terrible.
To enable the theme, open the chat settings (cog wheel) and enable Dark theme. By doing so, if you are a registered user, it will also save this in your user preferences and will remain the default until you change it back. Naturally it can also be set in your user preferences page too.
Furthermore, an additional set of colour alternatives has been added, to aid in recognition of different chatters in the feed. These are merely variants of the existing colours, with slightly different tones, though they should add some additional contrast.
I hope this will make chatting a lot more pleasant, though as always I am open to feedback if you have any suggestions or issues.