Possibility to change the margin of a page

As far as I can see, there is no possibility to change the margin of a page in Zoho Wiki.

Concretely it would be fine to be able to modify (in my case: to increase) the right margin.

The reason: At present, when writing longer sentences the lines become very long too, and this makes the text hard to read. By increasing the right margin, the lines would become shorter.

Ideal would be a funktion like the ruler bar in Word (so that I can make the changes with the mouse by moving a slider). Second best solution (less comfortable) would be an additional feature in the editor so that I can type in numbers which margin I would like to have.

(I know that you offer also page-centered themes ["Penguins" and "Green Valley"] where the pages are significantly smaller. But it would be better if the margin(s) for every page could be changed individually. Some need less space, some more because of the structure of the text or because of tables, pictures etc.)

Thank you.