Core Block CSS IDs

Drupal Core generates a number of blocks, each with a unique CSS ID. In Drupal 7, many of the core block IDs have changed so they more clearly indicate the purpose of the block.

Active forum topics
Drupal 6: block-forum-0
Drupal 7: block-forum-active

Author information
Drupal 6: block-profile-0
Drupal 7: block-profile-author-information

Book navigation
Drupal 6: block-book-0
Drupal 7: block-book-navigation

Language switcher
Drupal 6: block-locale-0
Drupal 7: block-locale-language-switcher

Most recent poll
Drupal 6: block-poll-0
Drupal 7: block-poll-recent

Navigation
Drupal 6: block-user-1
Drupal 7: block-system-navigation

New forum topics
Drupal 6: block-forum-1
Drupal 7: block-forum-new

Popular content
Drupal 6: block-statistics-0
Drupal 7: block-statistics-popular

Powered by Drupal
Drupal 6: block-system-0
Drupal 7: block-system-powered-by

Recent blog posts
Drupal 6: block-blog-0
Drupal 7: block-blog-recent

Recent comments
Drupal 6: block-comment-0
Drupal 7: block-comment-recent

Search form
Drupal 6: block-search-0
Drupal 7: block-search-form

Syndicate
Drupal 6: block-node-0
Drupal 7: block-node-syndicate

User login
Drupal 6: block-user-0
Drupal 7: block-user-login

Who's new
Drupal 6: block-user-2
Drupal 7: block-user-new

Who's online
Drupal 6: block-user-3
Drupal 7: block-user-online

Drupal 6 CSS style declaration:

/* Make the text in the user login block bigger. */
#block-user-0 {
  font-size: 1.5em;
}

Drupal 7 CSS style declaration:

/* Make the text in the user login block bigger. */
#block-user-login {
  font-size: 1.5em;
}