romanzolotarev.com is a Fediverse instance that uses the ActivityPub protocol. In other words, users at this host can communicate with people that use software like Mastodon, Pleroma, Friendica, etc. all around the world.
This server runs the snac software and there is no automatic sign-up process.
No, hiding sidebar toggle button under your logo is NOT a good idea.
Think about it from user’s POV: user needs to open a sidebar. They start to look for an icon that looks like a sidebar. How would they discover it under your logo? Only by accident. Users can’t click icons they don’t see.
Thanks nurikolan for reporting this.