All epub3 eresders I know honor orphans and widows. And if you (I mean the OP) wants to avoid widows, use the following code:
Code:
p {
...
orphans: 1;
widows: 2;
}
or
Code:
p {
...
orphans: 2;
widows: 2 !important;
}
The last option deals with paragraph of three lines forcing a single line at the end of the page and two lines at the beginning of the next. In all others cases will have (at least) two lines of text at the beginning and end of a page (with the last option). But personally, I prefer the first option.