I saw in a very old reply to a previous question that it is possible to mix whole pages with landscape and portrait orientation but haven't been able to find the CSS to do that.
@page{ size a4 landscape; } seems to apply to the whole document.

You can specify page using selector like:


@page spine {
size: 0.75in 8in portrait;
@top-center {
border-bottom: none ;
content: normal;
....

Jim Albright
Wycliffe Bible Translators

And then apply that page to a particular element using the "page" property.