If you want to create reports for printing, you shoul use another format than a web-site based on HTML. HTML is not designed to create printable A4 papers. But you can create a page which is exactly A4. But when doing that you should use a
reset css to remove margins and paddings from all elements, so that you have full control.
I would prefer to
generate a PDF-document for printing reports, but it should work using html.
A4 paper = 210 x 297 millimeters (8.27 x 11.69 inches), so I guess your header should be 7.5 inches (not 75 inches)