[barium]

For some calibre created epubs, I found the following, idiotic solution. I viewed the stylesheet.css for one, and noticed several .calibre# classes with formatting information.

E.g.:
.calibre1 {
border: 1px inset;
color: black;
display: block;
height: 2px;
margin-bottom: 0.5em;
margin-left: auto;
margin-right: auto;
margin-top: 0.5em
}

In my userStyle.css, I replaced the formatting in ALL of those classes with my desired formatting for the p {} tag:

.calibre1 {
line-height: 1.06em !important;
margin-top: 0 !important;
padding:0;
etc.
}

.calibre2 {
line-height: 1.06em !important;
margin-top: 0 !important;
padding:0;
etc.
}

And that worked. Now news downloads, and other calibre created epubs, look more or less the way I'd like them to. A lot of formatting is ripped out, of course. And there are some gaps, because some calibre epubs use more classes than others, but I think that should be easy to fix by simply adding more .calibre# classes to userStyle.css.

ePubs created elsewhere, though, use different classes and tags, but I guess coming up with several commonly used classes and tags and ripping them out using the userStyle.css file in the same way should help.