[CSS21] Default table border width in collapsing border model

Hello,

I'm having a hard time understanding the text describing the collapsing border model, 17.6.2:

http://www.w3.org/TR/CSS21/tables.html#collapsing-borders

Before entangling in complex descriptions, here's an example that I do not understand the rendering of. It seems all major current browsers agree in their rendering, but i don't see how their rendering agrees with the spec.

All browsers render the left border of the cell in the second row with a rather thin red line, when I would expect it to be 25px wide (initial left border width of the table, calculated as per 17.6.2) instead.

Test case:

--snip--
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title>Collapsing borders model table border default width (=half of first cell's collapsed border width)</title>
        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#collapsing-borders" />
        <style type="text/css">
            table
            {
                border: solid red;
                border-collapse: collapse;
            }
            td
            {
                background: transparent;
                border: 50px solid blue;
                padding: 10px;
                width: 100px;
            }
            td#c2
            {
		border-left: none;
            }
        </style>
    </head>
    <body>
        <table>
            <tr>
                <td>This cell has a 50px blue left border. This is the first cell's collapsed border width.</td>
            </tr>
            <tr>
                <td id="c2">There should be a 25 pixel wide red border on the left, centered vertically with the blue border above. (25px is the calculated default table border width, i.e. 50px/2 .)</td>
            </tr>
        </table>
    </body>
</html>
--snip--


Why is that?

Regards,
Christian

Received on Wednesday, 4 January 2012 15:15:21 UTC