Bug 287619 – ruby text shifts to left when negative-margin is applied

• Component: Layout and Rendering
• Status: NEW

[Takao Baba]

Created attachment 474219 [details]
result on safari and chrome

## Steps to reproduce

1. Open https://jsbin.com/pazikuxilo/edit?html,output

## Expected behavior

The ruby text "a" should be aligned to the center of the ruby base "あいう".

## Actual behavior

The ruby text is aligned to left.

## Note

This style is usually used for long <rt> that excess the ruby-base width: to avoid extra spaces to the adjacent elements.

Chrome and Firefox works well.

[Karl Dubost]

Created attachment 474261 [details]
rendering in safari, firefox, chrome

Hi Takao, 
Thanks for the report.
Testing on 

Safari Technology Preview  213          20621.1.11.111.1
Firefox Nightly            137.0a1       13725.2.16
Google Chrome Canary       135.0.7020.0  7020.0

I see the same layout for all rendering engines.

[Karl Dubost]

Created attachment 474262 [details]
rendering in safari, firefox, chrome

OK I see it. My bad. let me upload a testcase.

[Karl Dubost]

Created attachment 474263 [details]
testcase

testcase with a negative margin applied on rt.
It has no effect on Chrome and Firefox.

[Karl Dubost]

Created attachment 474264 [details]
rendering in safari, firefox, chrome

We see better witgh background colors applied.

    rt {margin-inline: -2em;background-color:gold}
    ruby {background-color: pink;}

[Radar WebKit Bug Importer]

<rdar://problem/145202236>