Deleting site-wide custom styles
To remove existing site-wide custom styles, follow these steps.
In the Manage Custom Styles window, click the
Trashcan icon next to the custom style you want to edit. In this
case, we are deleting the custom style BlueAllOver.
In the Delete Confirmation window, type
DELETE, and then click Delete.
Notice that the recently deleted style is no longer listed in the Manage Custom Styles window.