I was going to comment the same. The first change to the text color was to #555, which IMO is way too light already. Something like #333 works much better at "softening" the sharpness of black over white while still maintaining the text pretty readable.
But after that step the tutorial redefined the text color to #566b78, which is even lighter. I understand that the blue shade is a nice touch, but decreasing the legibility of the text so much is not.
Besides these nitpicks, the article is great though :)
Maybe it's a matter of screen quality? I don't have the best eyesight, but I saw no discernible difference between the #000 and the #555 when it switched. And neither were either too harsh or too soft on my eyes. But I was looking at it on a macBookPro.
Almost very designer I've worked with has eschewed black in favour of one of the lower order grays, not just to make the contrast less jarring but also to ease the browser's own font smoothing a little as it tries to jump from 0 to 255.
You could probably get a similar effect by softening the background color from a harsh #FFF. You might not need to use as light of gray text color then.
Yeah, i suspect that might be the case. The author may have designed this on a similar high-contrast screen too. I saw it on a regular 1366x1024 laptop screen and the reduction in contrast from black to #555 was discernible.
I saw this on a 1080p 15.4" display and whilst the switch to #555 was not especially jarring in itself, it made the harshness of the perfectly white background more prominent.
But after that step the tutorial redefined the text color to #566b78, which is even lighter. I understand that the blue shade is a nice touch, but decreasing the legibility of the text so much is not.
Besides these nitpicks, the article is great though :)