The .lastheading {depth}^[docs] function makes it possible to reference the last heading of a given depth across pages or slides.

Used in combination with page margin content, it allows for persistent headings, such as chapter titles or section names, to be displayed in the page margins.

depth refers to the heading level: 1 for #, 2 for ##, and so on.

.pagemargin {topcenter}
    *.lastheading depth:{1}*

# Chapter 1

.repeat {10}
    .loremipsum

Note that headings of lesser depth reset the last reference. In the following example, the depth-2 persistent heading is shown when on a depth-2 section (page 2), but resets when entering a depth-1 section (page 3):

.pagemargin {topleft}
    *.lastheading depth:{1}*

.pagemargin {topright}
    *.lastheading depth:{2}*

# Chapter 1

.repeat {6}
    .loremipsum

## Subsection

.loremipsum

# Chapter 2

.repeat {2}
    .loremipsum