How to adjust margins without messing up gutter margin

Sending again since subject was the same…

Hey everyone,

We have started on making Bloom books from the popular Cat and Dog series. We will make them available for Phone and Print. Since they are Creative Commons licensed,
we will share them via


We would like to adjust the margins on the standard A5 Portrait book. So, we created a CustomBookStyles.css. (see attached)

?? What we don’t know is; How to control the gutter margin.

Any help is highly appreciated.

If we add a CustomBookStyles.css like this it messes up the gutter margin

See my reply to Adjusting margins on Basic books