Office 365 Alternate CSS

  1. Navigate to the site or subsite you want to delete.
  2. Click Settings button at the top of the site or subsite, and click Site settings.
  3. Click Delete this site under the Site Actions heading on the Site Settings page. If Delete this site doesn’t appear on the Site Settings page, you may not have permission to delete this site, or you’re trying to delete a top-level site
  4. On the Delete This Site page, verify that you are deleting the correct site, and then click Delete. Ref: