SMACSS

Over 4 years ago, Alan Burke noticed that Drupal didn't have any CSS coding standards. He asked the documentation team lead at the time, Addison Berry, for advice and she suggested that if they wrote the first draft of the CSS coding standards, that would get the ball rolling on discussing them. The goal being to write, iterate and come to consensus on Drupal’s coding standards. See http://groups.drupal.org/node/14421 for the original discussion.

Unfortunately, its 4 years later and the CSS coding standards are still marked “Draft”. http://drupal.org/node/302199