The epub file is easier to understand rather than a separate css list.
The para is here...
PHP Code:
div.header.boxed-text .para {
display: block;
margin-top: 0.6em;
line-height: 150%;
}
and it is adding .6em spacing and an oversized line height.
Your choice is to remove that margin-top value (might have unintended consequences in other parts of the book for the div.header.boxed-text use
or
remove .para from there and add it as a separate entry in the css without the spacing. eg...
PHP Code:
.para {
display: block;
margin-top: 0;
margin-bottom: 0;
text-indent: 1em;
}