Problem/Motivation
This drupal.org documentation page describes many common pitfalls of Drupal module's CSS: http://drupal.org/node/1887918#pitfalls
Proposed resolution
To remove these problems, we should follow the best practices guidelines outlined on this drupal.org documentation page: http://drupal.org/node/1887918#best-practices
Remaining tasks
The work for this issue is being done in the Drupal 8 Mobile Initiative sandbox: http://drupal.org/sandbox/d8-mobile
User interface changes
None. The design objects that style the Drupal module's functionality should be look roughly the same after as they do now.
API changes
All of core's modules will have new CSS selectors that better match the design objects being used for their content.
Related Issues
This is one issue in the larger #1921610: [Meta] Architect our CSS issue. This issue combines work done in the Drupal 8 Mobile Initiative sandbox: http://drupal.org/sandbox/d8-mobile