How to get differently-sized header or footer depending on page number?

[Andrew]

@maven

Unfortunately, my question is still not answered.

@maven

How to do something similar for the size of header and footer, meaning page margins? Imagine wanting a much larger footer on odd pages, for example.

I don’t understand how this does not answer the question:

@Andrew

For margin it’s practically the same thing as the example with fill:

set page(header, footer) + context page(margin)[]

#set page(fill: gray, height: 4cm, width: 6cm)
#let is-odd-page() = calc.rem(counter(page).get().first(), 2) == 1
#set page(
  header: context if is-odd-page() [odd] else [even] + " header",
  footer: context if is-odd-page() [odd] else [even] + " footer",
)
#for n in range(1, 5) {
  context page(margin: if is-odd-page() { 1cm } else { 1.5cm })[
    page #n
  ]
  n += 1
  pagebreak(weak: true)
}

The code does allow you to have a much larger footer/header (margins) on odd pages than on even pages. Well, actually, I messed up a little, I set smaller margins for odd pages, but the fix is to just swap the values:

context page(margin: if is-odd-page() { 1.5cm } else { 1cm })[

Maybe you mean how to do the same thing but without calling context page()[] or context [#set page();] at the start of every new page? Meaning, you are only allowed to call set page() once at the very top of a document. Then I don’t think it is possible.

@maven

By the way, there is a simple workaround for fill, using background

If I now understand correctly, then sure. There is a similar topic, where I wrote a post comparing page.fill and page.background.