Well, I must say that’s a very nice start on macOS – I’ve just had a quick play.

The most obvious missing function at the moment is search, but the layout is elegant, the approach is valid. I like the automatic strikethrough of tasks, and I very much like the notes.

I’ll take another look when I’ve got a little more time and make some suggestions. Search, for me, is one of the key functions, however (and search that looks inside folded paragraphs! There are a couple of outliners out there which don’t find text if it’s inside a folded section (notably Numbers, which has a rather good folding function); this is a disastrous shortcoming!

Good job! Keep it up.

Cheers,
Bill