#Headings

#What it is

The line that cuts a document into sections. Six levels: the more #, the lower the level.

The side menu is generated from headings, and every heading gets an anchor you can link to.

#How to write it

# Level 1
## Level 2
### Level 3
#### Level 4
##### Level 5
###### Level 6

The hash marks need a space after them. #Heading is not a heading, it is ordinary text. Neither is seven hashes.

#What comes out

Size, weight, spacing and colour are entirely up to the theme, and they differ a lot:

The same document under a different theme looks completely different; not a word of content changes.

#The first heading is the document title

The first # becomes the output's <title> (the text on the browser tab), unless you set title in frontmatter.

It also does not appear in the table of contents — the ToC navigates within the document, and the document's own title is not a section of it.

So: start sections at ##, and write exactly one # per document.

#How anchors are computed

Lowercased, spaces to hyphens, punctuation dropped, non-Latin characters kept as they are. When two headings collide, the second gets -2.

For an in-document jump write [go to callouts](#callouts).

#Traps

• The ToC only collects to level 2 by default. For level 3 and below set toc: { deep: 3 } in frontmatter — see the frontmatter reference
• Don't use a heading to make text bold. Use **bold**; a #### pollutes the ToC and the document outline
• A tab's directive label also becomes a real heading and enters the outline — which is why toc.skipTabs defaults to true