Upgrade lightningcss to 1.29.0

[philipp-spiess]

Closes #15438
Closes #15560
Closes #15561
Closes #15562

This PR upgrades lightningcss to 1.29.0 and uses the new feature flag to disable the light-dark function transpilation.

[RobinMalfait]

Just a question, but apart from that looks good!

[RobinMalfait]

I wonder if this is enough. The list-style: none; expands to:

list-style-position: initial;
list-style-image: initial;
list-style-type: none;

So if another stylesheet sets the list-style-position or list-style-image to something else then this would be a breaking change technically.

However, I think our main goal was to use list-style-type: none; in the first place to get rid of the visual dot/number.

[philipp-spiess]

@RobinMalfait Not sure I understand, preflight is for normalizing user-agent styling and there initial is the default anyways, right? Any other stylesheets that could change this are probably in a different layer/unlyaered so they'd take presedence or am I missing somehting?

[RobinMalfait]

I just wanted to be 100% sure that this is the correct fix without causing other (subtle) issues since the computed styles would be different.

I think a lot of people will use @layer base for their preflight resets as well. I was trying to come up with an example where this change would not be enough/cause issues. E.g.:

If the setup looks like this:

/* ./styles.css */
@import "tailwindcss";
@import "./my-base.css";

/* ./my-base.css */
@layer base {
  ul {
    list-style-position: inside;
  }
}

If you then inspect a ul on the page, before this change, the styles would look like:

After this change, the styles would look like:

So while there is a difference in the computed values (the list-style-image is gone) I don't think there is an actual issue. I was trying to come up with an example where this wouldn't be the case but couldn't find any so far (which is good 😄)

[RobinMalfait]

Actually, it's just the devtools that hide the list-style-image, window.getComputedStyle() does have a none value for list-style-image.

[philipp-spiess]

Hmm I think it would only be an issue if the initial CSS looks like this, right?

/* ./styles.css */
@import "./my-base.css";
@import "tailwindcss";

i.e. the overwrite comes before our resets. However, that also meant you had CSS in there before that was overwritten anyways so chances are that they'd have reordered this already otherwise this has had no effects I think?

[RobinMalfait]

😍

[RobinMalfait]

Wew, finally!