W3C home > Mailing lists > Public > www-style@w3.org > April 2005

Re: User constant declarations in style sheets

From: David Woolley <david@djwhome.demon.co.uk>
Date: Wed, 27 Apr 2005 07:32:24 +0100 (BST)
Message-Id: <200504270632.j3R6WOU02641@djwhome.demon.co.uk>
To: www-style@w3.org

> I can't see why. In the example the lines would always be in proportion
> to the font. If you use absolute measures, increasing the font size could
> make the lines overlap. Perhaps there is a catch you might care to explain.
> 
Overlapping is exactly what happens if you, like most people who use
line-height, use anything except pure numbers.  If you use em sizes,
the line height is only correct for the font size on the element for
which the line-height property was applied.  If you use 1.2, as does
the specimen style sheet the CSS specification, the line height is
proportional even if the font size is changed in a sub-element (possibly
by another style sheet). 

> 
> Well, that is what grammars are for, isn't it? They are with us since quite
> a while now.

The key design rule for CSS grammars is backwards compatibility.  All new
syntax must result in the new construct being ignored by browsers that 
don't support the new features.

> 
> Absolutely not. If you want to keep the text in phase, you must make sure

I would say that was well beyond the scope of CSS.  It will break as soon
as another style sheet intervenes.  CSS should be designed on the basis that
you are not the only person controlling the layout.  If you want absolute
control, please use tagged PDF instead.

> If every proposed feature is going to be rejected purely on the basis of
> browsers being immobile, then why bother with CSS3 at all? On this list

It is a fundamental design principle of CSS that new features should not
prevent older browsers from interpreting the parts of the style sheet they
understand.  It also ought to be a fundamental design principle of "web
designers" to ensure that, for example by preceding a rule for a new feature
with a fall back rule, that their designs also exhibit that backwards 
compatibility.
Received on Wednesday, 27 April 2005 06:47:47 GMT

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