[publican-list] Code Samples highlighting colours

[Ryan Lerch]

  I was looking at the updated styles for <programlisting>s and noticed 
that some of the colours used to highlight the different elements of 
code in them can be a little hard to see (and sometimes a bit jarring)

Does anyone have any thoughts on the current default colours used, and 
maybe some thoughts on a better palette to use for this highlighting?

cheers,
ryanlerch