ADE on PRS 505 (Linux here, dunno if it affects x86 ADE) happily obeys "width" property for hr tag:
Except I have a hell of a time trying to center such a shortened horizontal line. Throwing "text-align:center" CSS property into hr itself doesn't work, nor does it work in "p" and/or "div" wrappers around "hr" tag.
I also tried display:block/margin-right:auto/margin-left:auto method (as described
here) in all three (hr, p, div) tags, but no joy.
Everything mentioned happily works on both Firefox and Calibre's EPUB viewer.
The <p style="text-align: center">n times "em-dash"</p> "workaround" is ... just ugly.
Is there another way?