@kovid, can't log-in to bug-tracker.
( Oops! Sorry, something just went wrong in Launchpad Login Service. )
For an quick example which shows the problem, in sigil, I created a new file, and all html of first page was :
Code:
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<style type="text/css">
h1 {margin:5em 0;text-align:center;}
</style>
</head>
<body>
<h1>Part One</h1>
</body>
</html>
When displaying as flow, the top-margin is respected and displayed as required vertical position, but with the paged mode, (without the override margins) the top-margin is ignored and the header is displayed at top of page, rather than the desired offset.
Here's the file that sigil created.