Rich text
Select this important sentence and change its formatting.
A second paragraph can become a heading.
Paragraphs, headings, quotations and inline marks share one immutable document.
A block describes structure; a mark describes a text run. Selecting text and toggling a mark can split runs without changing the surrounding paragraph.
Select words, apply bold or italic, then turn a paragraph into a heading or quote.
Select this important sentence and change its formatting.
A second paragraph can become a heading.
The same commands drive keyboard shortcuts and toolbar buttons. SetHeading(None) returns to a paragraph.