Customizing Facebook Comments
Hover over a Facebook Comments element to display the Edit button in its top right-hand corner and be able to modify the settings and design:
NUMBER OF COMMENTS: drag to select the number of comments to be displayed in the Facebook Comments widget.
COLOR THEME: select the color theme for the Facebook Comments widget: Light or Dark.
DISPLAY BY: select how Facebook comments will be sorted in the widget: by most popular comments, by newest comments, or by oldest comments.