I'm guessing you changed it since this feedback, but I really like the current color scheme. The lighter-grey bubbles around the actual code do a nice job directing focus to the important bits.
It was a very subtle change but yeah we lightened it up a bit after the feedback from this thread. We made quite a few changes actually and summarised them here: http://alias.sh/thank-you-hacker-news-community
I was instinctively looking for a modal window to close to make the colors vibrant again. It's a somewhat jarring experience.
A very easy to read grey on a very nice grey background.