[css-conditional-3] Are there issues with !important in @supports? (Is the grammar wrong?) #5559
Description
@SimonSapin [wrote on www-style in 2013](
Le 30/04/2013 07:44, John Daggett a écrit :
I've updated the CSS3 Fonts draft based on Simon's feedback.
AFAICT, the point of <descriptor_declaration> is to not have the
production for !important. You could, like @supports, refer to
defined in the Core Grammar instead.
Does @supports specifically ban the production? I don't see
the language in there for that. It's a relatively minor point but I
added the production to be clear that '!important' has no function in
@font-face rules (there have been issues brought up in the past in
relation to this).
I just assumed that because @supports defines explicitly
by referring to Chapter 4:declaration : property S* ':' S* value;
rather than Appendix G:
declaration
: property ':' S* expr prio?
;
But I was wrong. !important is allowed and has no effect. This is
specified in section 6, just before section 6.1:
A trailing ‘!important’ on a declaration being tested is allowed,
though it won't change the validity of the declaration.For example, the following rule is valid:
@supports (display: flexbox !important) {
// ...
}