Funny, when I first saw it I wasn't sure if my monitor was screwed up, whether someone had defaced HN or if some Chrome plugin was misbehaving. Though I eventually figured it out with the alternating red/green submission colors and HNSearching for "Christmas CSS". I also found out that you could change your topcolor and immediately set it to #000000 so people would stop pestering me when they saw I was reading a hacker website.

I've personally chosen to go for style rather than discretion and set it to #99cc33. It's been almost two years I think now and I really like it this way.

You can see what colors people are using here: https://news.ycombinator.com/topcolors. I don't know how they are sorted.

Also, if you want to remove the "Hacker News" text from the topbar and keep the rest of the text readable, it's easy to do with some CSS. For instance in Firefox's userContent.css you can add:

    @-moz-document domain(news.ycombinator.com) {
      .pagetop b { display: none; }
    }

"I also found out that you could change your topcolor and immediately set it to #000000 so people would stop pestering me when they saw I was reading a hacker website."

Thank you!!

:) I've actually just changed it to #333333 so I can still kind of make out the shapes of [threads] and [myusername] when I want to click on them.

If anyone who frequents hacker news shoulder-surfs you, they'll wonder who died.

What does that mean?

Once you reach a certain karma threshold, you gain the ability to change the colour of the orange bar at the top of HN pages. The setting is labelled 'topcolor'.

Off topic, but why the heck does this require karma?

The required karma threshold is not much (500 if I remember), so it may be a way to say "thanks and keep going" to people who start investing some time to participate to HN.

It means if you change header colors of HN website nobody can guess that's actually HN.

#000000 is black in HTML. setting your top color black would make the text in the top nav invisible.

That is exactly the point. They don't want people seeing that they are on HN.

Right, I got that. I was explaining it to my parent. :)

Wow, I'm slow. I assumed the red and green was a new feature that showed whether a story had recently risen (green) or fallen (red) on the front page — so you could better keep track of trends. I didn't notice they were consistently alternating.

I thought that too.

Excellent. Thanks!