Don't we want the styling to be at least this specific to encourage use of the idiomatic [header group pattern](http://www.google.com/url?q=http%3A%2F%2Fwww.w3.org%2Fhtml%2Fwg%2Fdrafts%2Fhtml%2Fmaster%2Fcommon-idioms.html%23sub-head&sa=D&sntz=1&usg=AFQjCNFE03bqcx5PPoA-_mqwWvlAuuUgIg) you sent me?