CSS extensions

I think we should have a page that lists CSS extensions intended to be 
used in themes and such and also lists related bugs.

For example, to make themes i18n ready they'd better use 
'-moz-margin-start' and '-moz-margin-end' instead of 'margin-left' or 
'margin-right', which are language dependent.

Example of a related bug: 
<https://bugzilla.mozilla.org/show_bug.cgi?id=260715>.

I think there also should be a document that discourages people to use 
CSS extensions like '-moz-opacity'. And that if they use them, they use 
'opacity' as well since we might remove support for '-moz-opacity' in 
the future. (Note that that document should *not* list our CSS 
extensions, it should just discourage people from using them, because we 
might drop support for them.)


-- 
  Anne van Kesteren
  <http://annevankesteren.nl/>