Welcome to WebmasterWorld Guest from 220.127.116.11
Forum Moderators: not2easy
If RGBA values are not supported by a user agent, they should be treated like unrecognized values per the CSS forward compatibility parsing rules ([CSS21], Chapter 4). RGBA values must not be treated as simply an RGB value with the opacity ignored.
The part I can't figure out is whether you can make a "first choice, second choice" formulation, in the same way that you can offer a comma-delimited list of fonts.