I found and applied this at home a while ago, but just thought to do it on my portable Firefox. It's made by José Pedro Arvela, who posts here.
Long story short, it turns all the red text blue and the red banners blue. The front page logo is changed, and the "YOUR DIGITAL LIFE, ANYWHERE™" slogan gets changed to a lighter shade of blue, as opposed to a lighter shade of red. The link in the announcement banner stays red, I guess the CSS doesn't look for links there to change. Should be a simple edit for someone who knows CSS. I don't, so I just deal with it. There are side-by-side screenshots at the link above, which will prompt you to install it if you have Stylish or Greasemonkey installed. (There's probably a manual way to install the CSS if you're not using Firefox, but I couldn't tell you what it is.)
I just think the blue's easier on the eyes.
And it doesn't remove the ads, either. A lot of Stylish themes do that, and I won't use one that does... at least not on sites I whitelist with Adblock Plus, such as here. (It doesn't change the thin red border around the ad frame, either...)