Pages in Fancybox, how is it implemented?

Question

fancyBox

Good evening
, I want to implement a portfolio on fancybox on the site, just like at the Altima studio.
I still can’t figure out how it’s done
in their portfolio section, when you click on a job, the page is loaded through fancybox - it’s as if it’s clear
that the link to this page is given a class,
but if on directly enter the address of the page, again they open through fancybox
, but for me it just loads the page along the direct path
, I can’t understand how they implemented it
, they somehow have different types of pages or how?