2.4.1. Specifying quotes with the quotes property
https://drafts.csswg.org/css-content/#quotes-property

auto
A typographically appropriate used value for quotes is automatically chosen by the UA based on the content language of the element and/or its parent.

Note: The Unicode Common Locale Data Repository [CLDR] maintains information on typographically appropriate quotation marks. UAs can use other sources of information as well, particularly as typographic preferences can vary; however it is encouraged to submit any improvements to Unicode so that the entire software ecosystem can benefit.

The i18n WG raised an issue related to the Rendering section of the HTML spec because current implementations choose quote marks based on the language of the quotation, rather than the language of the surrounding text. This is wrong, and needs to be fixed.

It is noticeable when the language of the quotation is different from that of the surrounding text. See these tests:

• https://w3c.github.io/i18n-tests/results/the-q-element.html#ml_nesting
• https://www.w3.org/International/tests/repo/results/the-q-element.en.html#ml_nesting_html
• https://www.w3.org/International/tests/repo/results/the-q-element.en.html#ml_nesting

Since the HTML spec is now to have that section removed (due to introduction of the auto value for the quotes property), we need this requirement to be made clear in the CSS spec.

[Note, btw, that contrary to the request at the start of the HTML thread mentioned above (https://github.com/whatwg/html/issues/3636), it is important to base the choice of quotes on the language of the immediately surrounding text, not the language of the html tag (as is made clearer further down the discussion thread).]

It would also help to include a note showing how content authors can make their styling produce the correct results (since it's far from straightforward, and it will no longer be possible to point to examples in the HTML spec).