It is possible to set a max height or a height to a page div?

i'm using a module (custom_background in the app store) that sets a pdf as background to the entire page, this pdf i set as background has some decorative elements on the corners, over this background is placed the report generated by the report engine and this one comes with a white background, so when it reaches an specific height it covers the decorative elements, so that it's why i need to limit the height of the 'page' div.

i have this report with this structure inside of a web.basic_container:

i have already tried with these css attributes: max-height, max-height...  but it didnt work
div class=page

inside i have stuff like tables, text, etc.​