Tux: Not the canonical reference but in http://www.w3.org/MarkUp/html3/tables.html there is this:
Hint: You can achieve a similar effect to the above by using decimal alignment and using the DP attribute to set the alignment character to a convenient character, for example:
Each line in the table is then indented so that all the colons are positioned under one another.
<tr align=decimal dp=":">
name: <input name="name" size=18><br>
card number: <input name="cardnum" size=18><br>
expires: <input name="expires-month" size=2> /
<input name="expires-year" size=2><br>
telephone:<input name="phone" size=18><br>
And yes, Amaya is a reference browser, but that doesn't change it's incompleteness (acknowledged with respect to CSS, for example, at http://www.w3.org/Amaya/Amaya.html at the heading "Support for CSS").
BTW, I have used it and while it sure is painful to do so, I'm not sure I'd characterize myself as a masochist. Excuse me now, while I go back to reading some nearly unintelligible nodes. :-)