[Jellby]

Originally Posted by mtrahan

First, I see that "line-height" attribute was removed: is it because this element isn't really used by e-readers?

I'd say it's because it's too font-specific and, unless you want some special effect, it's better to leave it alone.

I see that "font-size: normal" and "font-variant: normal" (I let that one there thinking that it could help avoid smallcaps) were removed.

Those are often redundant, unless you have to override some previous (or default) setting.

And the font-size of the <h1> element declared with "x-large" value instead of em: why is it better to do this?

x-large is an absolute size (reader dependent), while ems are relative. I guess for your case ems are better. I prefer percents, though (2em = 200%)

Also is there an advantage to declaring the 4 margins separately instead of all on same line?

None that I know.

And, last question about css, why declaring the margins in pixels instead of em?

Pixels are absolute, again, and do not change when you change the global font size in the reader. Depending on where the particular margin applies, you may want one or the other.