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Re: CSS 2.1 WD and non-CSS presentational hints

From: L. David Baron <dbaron@fas.harvard.edu>
Date: Tue, 13 Aug 2002 09:34:23 -0400
To: www-style@w3.org
Message-ID: <20020813093423.B2593@is02.fas.harvard.edu>

On Tuesday 2002-08-13 09:50 +0200, Håkon Wium Lie wrote:
> Also sprach Coises:
>  > This change might also present difficulties for user agents which could
>  > otherwise implement user-selected presentational defaults as a (real or
>  > virtual) user style sheet; it would instead be necessary to modify the
>  > (real or virtual) user agent default style sheet to set these defaults.

I don't see any reason the "virtual" UA stylesheet would need to be
merged with the existing one in any way, since (1) users can't actually
see the specificity of the selectors in the UA stylesheets and the
presentational hints that aren't implemented as CSS rules don't even
have a clearly defined specificity and (2) the things that are
considered presentational hints (largely, if not entirely, attributes)
are things that should override everything else in the UA stylesheet.
In other words, I think the presentational hints could be implemented as
their own level of the cascade between the UA and user level without
sorting rules based on specificity and order.

That said, the new text is less precise than the old text since it
doesn't define the specificity of the presentational hints, and
therefore doesn't define how they interact with the rest of the UA
stylesheet.  Would it make sense to avoid this problem by saying that
the presentational hints are at their own level of the cascade, between
the UA level and user level?  Or would it be better to resolve the
problem by saying that the specificity of the style from presentation
hints is implementation-defined?

-David

-- 
L. David Baron        <URL: http://www.people.fas.harvard.edu/~dbaron/ >
Received on Tuesday, 13 August 2002 09:34:34 GMT

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