Firefox 63 prints pages of my website with blank spaces or broken pages, possible css conflict when printing?

Since a couple of years firefox can not print my website correctly (WYSIWYP) and I have tried all the possible and imaginable ways ... the only solution is to use the "simplify page" or to print with Chrome or with Opera ... there is something that escapes me in my css?

My website is self-produced by me, I only added Google Prettify...

I thought it was the fault of the display: inline-block; or overflow: hidden; but despite everything firefox still does not print my site or my pages correctly ... are there any possible solutions? To be more precise, Firefox prints my pages but are interrupted by useless white spaces or are even truncated ... what I do not understand is why my site is very well seen with Firefox but when I have to print a few pages (despite the fact that the print css is almost identical to that of the screen except for some cosmetic effects) I can not make a decent print? I am using Firefox 63.0.0. Ideas?

some links:

https://www.alecos.it/new/115/115.php

https://www.alecos.it/download.php

https://www.alecos.it/diary.php?page=1

and now some grabs: