Keys
A line is one block. It wraps across as many rows as it needs, and the weight
applies to the whole block.
N normal · B bold · H heading · T title.
An empty N line is your blank line.
Tab cycle line type · ⌘1–⌘4 set it directly
Enter new line · ⌫ merge up · ⌘Z undo
Select text for bold, italic, underline, colour and highlight.
Paste or drop an image to place it centred, with a numbered caption
underneath. Captions renumber themselves.