Apply a Cascading Style Sheet (CSS) helper class to a cell to alter its default styling or behavior in a small way, without creating a new skin format. For example, use a helper class to center an element in a cell.
On the Presentation tab of the Cell Properties panel, expand the Advanced Presentation Options section.
To display the Helper class picker dialog box, click the Open helper class picker icon for the Cell read-write classes field or the Cell read-only classes field.
To see a description of a helper class's effects, hover over its name in the dialog box.
To filter helper classes by class name or description, use the search field.For example, you might enter right to see helper classes for adjusting the right side of an element or enter margin to see helper classes for adjusting standard margins.
Select one or more helper classes to apply to the current cell, click Submit, and then click Submit on the Cell Properties panel.