Starting October 3, Google is rolling out the new look of Google Docs and Sites. The new look design focuses on highlighting your content with cleaner and more prominent menus, toolbars, and action buttons.
If you’re still not ready for the new look you can revert to the Classic look, via Help > Use the classic look. The classic look will be supported for at least a few more weeks.
For more info visit: Experience the new look of Docs and Sites | Docs Blog