[css-cascade-5] @layer preceding @import should be valid

[cdoublev]

According to 2. Importing Style Sheets: the @import rule, @import can precede @layer statement.

Any @import rules must precede all other valid at-rules and style rules in a style sheet (ignoring @charset and @layer statement rules) [...]

But it is not clear if it can be preceded by @layer statement (emphasize added):

[...] and must not have any other valid at-rules or style rules between it and previous @import rules

What are these other valid at-rules or style rules? Do they include @charset and @layer statements?

I guess @import can now be preceded by @layer based on 6.4.4.2. Declaring Without Styles: the @layer statement at-rule:

Such empty @layer rules are allowed before @import and @namespace rules

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Aside: I think that enumerating at-rules and style rules may not seem necessary and may be simplified to rules.

Any @import rules must precede all other valid rules (ignoring @charset and @layer statement rules) and must not have any other valid rules (ignoring @charset and @layer statement rules) between it and previous @import rules, or else the @import rule is invalid.

[cdoublev]

I found #6522. Based on its resolution, interleaving @layer statement between @imports, or interleaving @import between @layer statements, must be invalid. The current prose and Example 31 seem confusing then.

It’s also possible to have @import rules help establish the order, by placing them between @layer rules. This example will have the same result:

@layer default;
@import url(theme.css) layer(theme);
@layer components;

@layer default {
  audio[controls] {
    display: block;
  }
}

And it seems to also apply to interleaving @layer between @namespace statements, or vice-versa, as explained in this non-normative note:

Note: Any @layer rule that comes after an @import or @namespace rule will cause any subsequent @import or @namespace rules to be ignored.

Actually, this means you can declare @layer, @import, @namespace, in this order, but not @import, @layer, @namespace. I am confused.

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Aside (another simplification suggestion):

Such empty @layer are allowed before @import and @namespace rules (after the @charset rule, if any) as well as everywhere @layer block at-rules are allowed.

@charset is always ignored by the parser, according to CSS Syntax 3, therefore I think removing "(after the @charset rule, if any)" would avoid any confusion about @layer statement preceding @charset (valid, if I am not mistaken).

[cdoublev]

Requirements are quite fragmented and seem to lack specifics on their motivations, which makes them even more difficult to grasp, but after re-reading, there do not seem to me to be any contradictions (at least in CSS Cascade 5).