I'm trying to remove any margin settings in my epub files in order to use the margin sliders on the Glo. I have the patcher installed with "custom left/right margins" patch enabled. At first I thought the "ignore book css" patch would be a godsend but quickly learned why the css experts here said it was like using a sledgehammer to drive a thumbtack.
I would prefer to edit the epub directly so as not to have duplicate files in my Calibre library. I used Sigil on a few, changed all margins to 0 in the css stylesheet and everything was good.
I then encountered an epub where that didn't work, and some poking around revealed a
.xpgt file with margin settings. Does Kobo use this to display the epub? Would I set the single_column margin settings to 0? Deleting all these page-master references caused a corrupted database went I sent the epub to the device, so I'm a bit leery to mess with this file now.
I downloaded a fresh epub file and used Modify Epub and checked "Remove margins from Adobe .xpgt files" which had the desired effect, but that plugin does create a backup epub. I'd really like to learn to use Sigil to do this.