These 2 tests are testing what is the first page of a document whose
root element has its 'writing-mode' set to 'vertical-rl' and set to
I assumed that the first page of document whose root element has
'writing-mode: vertical-rl' is the left page because
Whether the first page of a document is :left or :right depends on the
major writing direction of the root element. For example, the first page
of a document with a left-to-right major writing direction would be a
:right page, and the first page of a document with a right-to-left major
writing direction would be a :left page.
CSS2.1 section 13.2.2 Page selectors: selecting left, right, and first
The principal writing mode of the document is determined by the
writing-mode and direction values specified on the root element. This
writing mode is used, for example, to determine the default page
progression direction. (See [CSS3PAGE].) Like direction, the
writing-mode value of the root element is also propagated to the initial
containing block and sets the block flow direction of the initial block
3.1 Block Flow Direction: the writing-mode property
Right now, Firefox 43.0a1 buildID=20150815090753 and Chrome 46.0.2478.0
fail both tests.
I do not know about IE11 or Edge12.