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- This WPT test may be referenced by the following Test IDs:
- /css/CSS2/margin-padding-clear/margin-backgrounds-002.xht - WPT Dashboard Interop Dashboard
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<head>
<title>CSS Test: transparency of margin area and background-color</title>
<link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
<link rel="help" href="http://www.w3.org/TR/CSS21/box.html#mpb-examples" title="8.2 Example of margins, padding, and borders" />
<link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background" title="14.2 The background" />
<link rel="match" href="../reference/ref-filled-green-100px-square.xht" />
<meta content="The margin area of an element is always transparent. The background-color of an element never paints its own margin area. The background-color of an element only paints its own border area (if any), its own padding area (if any) and its own content area (if any). Therefore the background-color of the content area (and of the padding area, if any, and of the border area, if any) of a parent element shines through the margin area of its child. In this test, div#parent is painted green and is 100px by 100px; its sole child has an 99px margin bottom and a 100px margin right margin which are transparent and through which we can see the background color of its parent." name="assert" />
<style type="text/css"><![CDATA[
p {margin: 1em 0em;}
div#parent
{
background-color: green;
height: 100px;
width: 100px;
}
div#child
{
background-color: red;
height: 1px;
/*
'height: 1px' is set intentionally so that the
top margin (16px) and bottom margin (99px) of such child
box do not collapse through the element.
*/
margin: 16px 100px 99px 0px;
/*
'margin-top: 16px' correspond to the margin-bottom of the
<p>. The margin-top of the child box collapses with the
margin-top of div#parent and then the collapsed margin-top
of div#parent then collapses in its turn with the
margin-bottom of the <p>.
*/
width: auto;
}
]]></style>
</head>
<body>
<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
<div id="parent">
<div id="child"></div>
</div>
</body>
</html>