W3C home > Mailing lists > Public > public-html@w3.org > April 2014

Re: Reasonable default styles and visual accessibility

From: Patrick H. Lauke <redux@splintered.co.uk>
Date: Tue, 01 Apr 2014 18:12:13 +0100
Message-ID: <533AF36D.9090105@splintered.co.uk>
To: public-html@w3.org
On 01/04/2014 17:47, Jens O. Meiert wrote:
> Is that true? HTML typically defines a default presentation [1,2]
> which is more or less faithfully followed by user agents [3].

The primary issue here seems to be line length, which by default spans 
100% of the viewport. I guess Simo is arguing for some clamping of 
HTML/BODY width which would result in a default line length that is more 

This relates to point 2 of WCAG 2.0 1.4.8 Visual Presentation (Level 

"For the visual presentation of blocks of text, a mechanism is available 
to achieve the following: (Level AAA)
1. Foreground and background colors can be selected by the user.
2. Width is no more than 80 characters or glyphs (40 if CJK).
3. Text is not justified (aligned to both the left and the right margins).
4. Line spacing (leading) is at least space-and-a-half within 
paragraphs, and paragraph spacing is at least 1.5 times larger than the 
line spacing.
5. Text can be resized without assistive technology up to 200 percent in 
a way that does not require the user to scroll horizontally to read a 
line of text on a full-screen window."

A very naive bit of CSS in the browser default stylesheet, along the 
lines of

html { max-width: 70em; }

or similar would do the trick...however, this would break compatibility 
with pretty much all current and legacy web content out there...so I'd 
say it's unlikely to be implemented. At best, browsers could be made to 
include a special "reader" mode perhaps that forces this, but users 
would have to explicitly turn it on/off.

Patrick H. Lauke

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Received on Tuesday, 1 April 2014 17:12:34 UTC

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