Your PDF files may need to be archived for security or legal reasons. In this case, the generated file must be compliant to the PDF/A ISO standard.
body { font-family: Arial }
@page {
@top-left {font-family: Arial }
@top-right {font-family: Arial }
@top-center {font-family: Arial }
@top-left-corner {font-family: Arial }
@top-right-corner {font-family: Arial }
@bottom-left {font-family: Arial }
@bottom-right {font-family: Arial }
@bottom-center {font-family: Arial }
@bottom-left-corner {font-family: Arial }
@bottom-right-corner {font-family: Arial }
}pdf.archiving.mode parameter from the list.