Re: [css3-namespace] XML Core WG's review

fantasai wrote about the 'namespace' at-rule in CSS:

> Prefixes are case-insensitive because CSS is case-insensitive. The only
> parts of a style sheet that are case sensitive are the parts that involve
> string matching against something outside of CSS (e.g. URLs, XML element
> names).

Authors and authoring software mint prefixes, and there is no prefix 
defined in any CSS specification. I would specify a comparison function 
that is sensitive to case, but I won’t make a fuss over the matter.

Insensitivity to case creates the edge case which the following style 
sheet demonstrates. Which declaration wins? Why?

/* U+0069 Latin small letter I */
@namespace istanbul url("data:,example");

/* U+0069 Latin small letter I */
istanbul|example {color: blue}

/* U+0131 Latin small letter dotless I */
ıstanbul|example {color: yellow}