Table Head Colors

The .thead-dark class adds a black background to table headers, and the .thead-light class adds a grey background to table headers:

Firstname Lastname Email
John Doe john@example.com
Mary Moe mary@example.com
July Dooley july@example.com
Firstname Lastname Email
John Doe john@example.com
Mary Moe mary@example.com
July Dooley july@example.com