firefox/testing/web-platform/tests/css/css-ruby/interlinear-block-margin-box.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-ruby/#interlinear-block">
<link rel="mismatch" href="interlinear-block-margin-box-ref.html">
<title>padding/border/margin should affect block-axis positioning</title>
<body>

<div>
<ruby>base<rt style="padding-bottom: 5px;">annotation</ruby>
</div>

<div>
<ruby>base<rt style="border-bottom: 7px solid transparent">annotation</ruby>
</div>

<div>
<ruby>base<rt style="margin-bottom: 11px">annotation</ruby>
</div>
</body>