Reima’s Shards

Does this refer only to different skill branches within the same specialization, or do different specializations also stack?

In the chat, Revan said that everything stacks within the bounds of logic. That is, any bonus to range from one-handed weapon skills will not have an effect, but different two-handed weapon styles stack with each other.
As for how the weapon skill style stacks with the two-handed weapon style (i.e., styles of different weapons, in terms of the damage bonus, for example), I might be wrong, but it seems that they don't stack either.