A CSS style sheet typically includes
one or more rules. You can edit an individual rule in a CSS style
sheet using the CSS Styles panel, or if you prefer, you can work directly
in the CSS style sheet.
In the CSS Styles panel (Window >
CSS Styles), select All mode.
In the All rules pane, double-click the name of the style
sheet you want to edit.
In the Document window, modify the style sheet as desired,
and then save the style sheet.