CSS HR Tests

<HR style="height: 2px; border-style: solid; border-color: #009; color: #00F; background: #00C; border-right-width: 0; border-bottom-width: 0">

<HR style="height: 2px; border-style: none; border-color: blue; color: blue; background: blue">

...but it's the padding attribute that Opera needs, for specifying height to work.
Use "padding-top: 0px" or "padding: 0px".

<HR STYLE="padding: 0px; margin-top: 8px; margin-bottom: 8px; height: 1px; border-style: none; border-color: blue; color: blue; background: blue" NOSHADE SIZE=1 COLOR="#0000FF">

OmniWeb, unfortunately, does not work with the same CSS that covers other browsers. We cannot use "background: blue" for it, even though it's needed by ChimeraNavigatorCamino and Safari v51-73. (ChimeraNavigatorCamino displays it as grey; Safari v51-73 doesn't display it at all.)

<HR STYLE="padding: 0px; margin-top: 8px; margin-bottom: 8px; height: 1px; border-style: none; border-color: blue; color: blue" NOSHADE SIZE=1 COLOR="#0000FF">

So, that's the skinny on colored horizontal rules. If you need them in OmniWeb up thru at least 4.1, then you must browser sniff and provide an alternate style sheet.
(Maybe I should put this info into a table for clarity...)

OBJECT in a TABLE

100% width table. 3 rows; top and bottom rows are spacers, middle row contains the OBJECT of type image/gif for a transparent GIF and has a blue background. OBJECT content has <HR NOSHADE SIZE=1> as fallback.