With css being the standard today people have stopped using the h tags for their headlines. Instead they are creating headline styles that look the same but are going to be treated differently by the search engines! Instead you should style your h tags to look how want them but still use them to show importance and make sure to keyword load your headline tags.
There is no way for google to or other search engines to know what styles are more important then other styles so they can’t work that into their algorithm. Maybe positioning plays a roll in it, but you will find it better to use the h tags with a style!