Updated: 8th of September 2013
After several months of waiting, FB no longer supports external CSS as of today. Here's my alternative to change the border color of the like box:
http://webtrick101.blogspot.com/2013/09/latest-method-to-change-facebook-like.html
Updated: 27th of February 2013
As of yesterday, this method is no longer working. Let's wait for a few more days and see if Facebook turns this feature back on.
Updated: 1st of March 2013 (Not Working Anymore)
If you use http://www.facebook.com/plugins/likebox.php instead of http://www.connect.facebook.com/widgets/fan.php as your like box script, you can still control the color of the iframe by adding the border style to it. As of now, the external CSS is still not supported.
Actually it is still supported but the method used has changed.
Here's the latest format/method:
<iframe style="height: 400px; width: 310px; border: 0" src="http://www.connect.facebook.com/widgets/fan.php?href=[FAN PAGE URL]&colorscheme=light&show_faces=true&stream=true&header=false&css=[CSS URL]"></iframe> |
Instead of using <fb:fan> tag, iframe is used. As for the [FAN PAGE URL], you can put something like http%3A%2F%2Fwww.facebook.com%2FmyFBpage. Please note that %3A means ':', %2F means '/'. The same goes for the CSS URL. Just point to a css file.
Enjoy!