In the CSS Properties panel you’ll see a message in the preview area. Instead of CSS code
(which is what the preview area typically shows), the message states that the object needs to be
named in the Layers panel or you need to allow Illustrator to create styling from “unnamed
objects.”
Open the Layers panel (Window > Layers), and click the Locate Object button ( ) at the
bottom of the panel to easily find the selected object in the panel.
Double-click directly on the name of the selected
object in the Layers panel, and
change the name to button (lowercase). Press Return or Enter to make the change.
Note
You may need to drag the left edge of the Layers panel to the left to see the entire name
of the object.