Custom iframe scrolling


I have a page where it has an iframe containing a pdf. This page is going to be used only with google chrome, on a touchscreen computer.

Now the problem the end user faces at the moment is that if the pdf is more than two pages long and they need to scroll down, the default scroll bars are too small to use for navigation with your finger.

Ive tried using webkit to change the style/format of the scroll bar which works but not in an iframe :frowning: example

Does anyone have an idea of how i can fix this problem, Even if there are custom up/down arrows on the page that will scroll the iframe. All i need is the end user to scroll up/down the pdf with ease (user friendly).

URL to page im trying to edit link.