This is what I use. The hr is the section break marker. It works in ePub, KF8, Mobi, KePub, and KFX.
Code:
hr {
margin-top: 1em;
margin-right: 40%;
margin-bottom: 0.9em;
margin-left: 40%;
border-top: 2px solid;
}
p {
margin-top: 0;
margin-bottom: 0;
text-indent: 1.2em;
}
.noindent {
text-indent: 0
}
Code:
<p>Last line of the section</p>
<hr/>
<p class="noindent">This is the first line of a new section</p>