When you sign in, the browser stores a solandra_session cookie. It keeps you signed in. If you are not signed in, that cookie is not there. Turning it off would drop the account session, so it is not optional.
The night and day choice is not a cookie. It stays in this browser as solandra-theme. The night-mode control in the menu changes it. It is not sent to another site.
There is no cookie that tracks the visit, shows ads, or sends data to a third-party network. There is no extra cookie list to switch off.
