For the small subset of people in the world who experience the “left margin issue” above when converting from EPUB format to MOBI format, here is a solution that works for me:
- Install Calibre and Sigil.
- Import your EPUB into Calibre.
- Convert the EPUB to EPUB. This normalizes the CSS stylesheet for the book. Under “Page Setup” set the left margin to 0.
- Open the new EPUB in Sigil.
- Open Stylesheet.css (or stylesheet1.css) (located under the “Styles” folder in the Book Browser on the left.
- Do a search for anything that says “margin-left” (or “margin-right”).
- If the value is anything other than “0”, change it to 0. E.g. “5pt” –> “0pt” or “1em” –> “0em” You will find multiple instances of this within the stylesheet.
- Save the EPUB and exit Sigil.
- Open Calibre and convert the EPUB to MOBI. Under “Page Setup” set the left margin to 0.
That should do it. It’s cumbersome, yes, but it gets the job done.
Based off of a post in MobileRead.com