pdf looks different in pdf reader than browser

[Yora]

I got a .pdf file that looks somewhat broken when I open it with Okular on Fedora 25, but seems perfectly fine when I open it with firefox. I believe the whole point of pdf is that it always looks the same? Why doesn't it seem to work?

[snowblizz]

Because software developers don't believe in following standards exactly. And because standards are designed by committee there are loopholes where two or more powerful entities can't get their own way.

Pdfs do a lot of work so it will matter a lot the way it was set up. If the pdfs is essentially pictures of a document it will looks the same everywhere but be rather large in size. If you want a much slimmer filesize and mroe flexibly useful document, say, forms you can enter stuff into it starts to become a lot more placeholders that are rendered differently in different programs.