I like it. It's different enough from Olivia that I don't think it will get lost. I would worry more about getting it mixed up with Lilliana, but since that's not as common, it's not really a problem. I think Livia on its own is way to close to Olivia, but Liviana is distinctive and feminine without being too girly. (I can see a judge or doctor Liviana before a judge Olivia.) All that being said, my first reaction was that it was a made-up name, but an interesting one.