We kept the existing post background colors to make transition easier and because they are really a classic diyAudio color set. We did lighten them a little as they were very dark before and we had complaints about lack of contrast. Unfortunately every monitor is different - brightness, contrast and color gamut - and what looks good on one looks bad on another. Additionally, as 99.9% (100%?) of us are male, fully 1/12 are colorblind in some form, so we have to try to cater for a lot
I can't currently see any reason why not to offer a higher contrast and lower contrast version of the website skin in the future, you might see that appear in the next week or two. The skin was finalized at the 11th hour so expect to see plenty of changes and improvements in it as time goes on as well.