A notebook is a page of cells that sits in your Library beside the things you kept.

Interesting Ideas, and everything on the page is mine.

A text cell takes prose, and markdown shortcuts turn into formatting as you type.

Cells save about a second after you stop, and again when you leave.

Then the at sign.

It offers three kinds: a Library item, a Highlight you made, an Annotation you kept.

Pick the item.

On its own line it becomes a reference card, carrying the real title and source.

Click it and you are in the piece itself.

A reference is a door back to the source, so it keeps up as the source changes.

Leave it for a year and the door still opens on the real thing.

The toolbar is formatting and structure: headings, lists, quotes, code, references.

The writing stays yours.

Your paragraph, and a door out of it.