OOo doesn't have external themes (the available ones are in Tools>Options>View>User interface). It should be possible to create custom but the process is not very well documented IIRC. And there is no extensions like Firefox. Is it what you were looking for?
AOO 4.1.7 on Xubuntu 19.10 and 4.1.5 on Windows 10 (with winPenPack port).
Hagar de l'Est wrote:And there is no extensions like Firefox.
What do you mean by this?
Have you looked at the 3.0 Beta and checked out the changes to the Extensions interface? It is rather like the Firefox extensions It's pretty nice, and anyone who is familiar with the Firefox addons will feel at home in the new Extensions interface.