theme_css_filename
Cascading Stylesheet (CSS) filename, relative to the style virtual directory, to be applied to the layout and weblets dependant on the layout. This will determine the style properties for HTML elements and the CSS class selectors available for selection on subordinate weblets' class properties.
Refer to Cascading Style Sheets (CSS) and the Style weblet for more information on the use of CSS in your layouts.
Default value
''Valid values
Any path and CSS filename, relative to the style virtual directory, enclosed in single quotes. A file can be chosen from a prompter by clicking the corresponding ellipses button in the property sheet.