Flexible structure (notebooks > sub-notebooks > notes), notebook level encryption, real-time sync, widely cross-platform, images (with light annotation), markdo

Flexible structure (notebooks > sub-notebooks > notes), notebook level encryption, real-time sync, widely cross-platform, images (with light annotation), markdown editing, zoom text (cmd/ctr-+), light-weight/fast, fantastic search, no tags. I'd like to share a notebook or make a note public, no chat. I will pay anything.