At least add the possibility of saving the page. Currently it blocks you for even doing that (other "invalid" code passes just as well)

Not being able to save unrecognized CSS is the entire point of TemplateStyles.

In T271958#8170354, @Tgr wrote:

Not being able to save unrecognized CSS is the entire point of TemplateStyles.

Which is why this task is asking to recognize this widely recognized CSS

Since Firefox 94 (2021-11-02) Firefox no longer requires the prefix per https://developer.mozilla.org/en-US/docs/Web/CSS/min-width#browser_compatibility .

@Ebrahim Could you look into this?

I think this could resolve this - https://gerrit.wikimedia.org/r/c/css-sanitizer/+/1052146

@Ioaxxere I'm not maintainer there and my patches struggle to get merged so you can ignore my feedback but since you pinged me here I want to say for the ease of finding reviewer on the patch please add Bug: T216897 in the below of your commit message there, add a test and add appropriate links, https://gerrit.wikimedia.org/r/c/css-sanitizer/+/1070601 may help as an example. https://www.w3.org/TR/2021/WD-css-sizing-4-20210520/#sizing-values can be a better link to add to README, inline comment and the changelog and since you are adding fit-content, I think you should also add stretch and contain in addition to fit-content, at least completing one section of a specification if not all of it.

https://www.mediawiki.org/wiki/Gerrit/Commit_message_guidelines :)

@Ioaxxere I can also take over some time later if you like to though I might have the same chance as you but I think developing the patch can be a fun by itself also.

Change #1074721 had a related patch set uploaded (by Eccenux; author: Eccenux):

[css-sanitizer@master] Support for CSS Box Sizing Level 4

https://gerrit.wikimedia.org/r/1074721

Tests seem to be passing. Please review. I have added the parent task: T375344. The task may not be formally correct, so if anyone could clean it up, that would be great :)