Re: [csswg-drafts] [css-borders] Add a 'hairline' border-width value (#3720)

I think the ideal solution would be to do all of:

 * A `hairline` keyword for line-widths. That's just convenience. I don't think anybody has any problems with this.
 * env(hairline) for use on everything. I think this can solve a lot of the issues that authors have.
 * A keyword to the `round` function (ideally) or a `border-round` function. I think adding an extra `line-width` keyword which would disallow a third argument to round() is probably slightly nicer? Anyways bikesheddable but it seems a requirement if we don't want to expose the plain dpx value, as otherwise you can't implement the right rounding behavior unless you assume env(hairline) is a device pixel.

I think we could do something parallel to 2 and 3 for device pixels, but separate issue :)

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Received on Saturday, 17 January 2026 07:13:22 UTC