CSS system colours - a (Windows centric) test page

The core page has no particular styling attached to it with regards to background colour, text colour, etc. IE diligently applies the system preferences to the document (provided that Internet Options > General > Colors > Use Windows Colors is checked), but other browsers (Firefox, Opera) apply their own default unless they've been specifically set up to use system colours (example in Firefox: tools > options > general > fonts & colors; Opera doesn't seem to allow system preferences, no matter what)

Test this by changing your system colour settings (in Windows, Control Panel > Display > Appearance - save your current one, if you haven't already, and choose something dramatic like "High Contrast"), then visit the page again (in most browsers, changes should happen without the need to even reload the document).

unstyled

depends on how the browser behaves with regards to unstyled documents.

this is a test link ... and another test link

system colours

in CSS2 compliant browsers, this section should display with the user's sytem preference colours for background, text, highlighting (tabbed links)...even if the browser has not been specifically instructed to do so. system colours are effectively forced via CSS2.

this is a test link ... and another test link

explicitly styled

and here's what most of us do: explicitly set colours when creating the CSS. unless your browser is set to override them, they will be applied regardless of system preferences.

this is a test link ... and another test link

conclusion

for accessibility, it may be worth considering using CSS2 system colours. they seem to work across the patch for CSS2 compliant browsers, and offer advantages when you want to apply system colours to elements, effectively overriding any browser defaults you'd normally get if left completely unstyled. maybe not in the default stylesheet, but as an alternative stylesheet.