Great point. Our environmental factors are so easy to forget. I do use a very high contrast monitor and definitely prefer pastel colors at night, so my eyes dont hurt, but now I can clearly see how someone with low contrast wont' see a damn thing.

There is a solution, but it's a bit more complicated and requires introducing additional user preferences. Supply two color options in the css, and allow user to choose high/low brightness.

HN already has some profile filters, so adding one more might not be a problem, but I can also see how it becomes a slipper-slope of new features.