More specifically, it looks like we honor the `size` from the `:first` page style, but not `margin` or `page-orientation`. Updated testcase coming to demonstrate that.
Bug 1859830 Comment 3 Edit History
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More specifically, it looks like we honor the `size` from the `:first` page style, when determining the paper size. But we don't honor the `margin` or `page-orientation`. And we don't honor the `size` when determining the page size; we just use whatever we get from the paper (which happens to be correct if we're using the save-to-pdf print target). Updated testcase coming to demonstrate that.