This CSS section of the developer guide is a holdover from the desktop widgets reference. I'll follow up with engineering to see what parts (if any) are supported for TV Widgets.
Only the following fonts are supported:
Helvetica Neue (normal, bold, italic and bold italic) Helvetica Neue Condensed (normal and bold) Helvetica Neue Light (normal and italic)
Note that Helvetica Neue Condensed is a font name and not a variant of Helvetica Neue. To select it you must set the fontFamily=”Helvetica Neue Condensed” and not fontFamily=”Helvetica Neue”, fontStretch=”condensed”.
As a widget developer you cannot add additional fonts with your widget installation. We'll update the CSS Reference section to reflect this.