Way back when, in the early days of CiviCRM, there were two CMS’s supported, Drupal and Joomla, and CiviCRM’s codebase was complicated, but ran reasonably well. After a few years, the code was greatly improved but also significantly expanded to include a tremendous amount of additional functionality, and thus CiviCRM became a serious server resource hog. Finding hosting that could run it at all was sometimes a challenge and finding a host that could run it well was difficult.
- Customizing CiviCRM templates
- Custom CSS in a Joomla! template or Drupal theme
- Custom jQuery code