Custom print format with water mark

this link -
https://frappe.github.io/erpnext/user/manual/en/setting-up/print/letter-head.html
and
this - https://frappe.github.io/erpnext/user/manual/en/setting-up/setup-wizard/step-5-letterhead-and-logo

does not work anymore…
any other alternative to the above solution will be much appreciated.

absolute position with z-index thing in HTML is not giving desired output
also flex not working as required.