Question: Why was the border box rule changed?

[mattpilott]

Hey,

I see way back in v6 the border-box rule was changed from inherit from html to being explicitly defined, why was this decision made out of interest?

Thanks

[hacknug]

I believe it was because pseudo elements don't inherit the value from their parent: https://github.com/csstools/sanitize.css/blob/master/CHANGELOG.md#600-june-24-2018

EDIT: Here's a comment from @jonathantneal explaining why jensimmons/cssremedy#4 (comment)

[jonathantneal]

@matt3224, that’s a fair question. I dropped the inheritance strategy for 2 reasons.

1. The CSSWG has determined that box-sizing should be border-box by default. However, to keep the web backwards compatible, specs and browsers will continue shipping content-box as the default. Therefore, making border-box the default in sanitize.css is more “standards facing” than the inheritance strategy.
2. The individual “responsible” for the inheritance strategy now agrees with the CSSWG. I know because I am that person.

My motivation for the inheritance strategy was to “make it easier to change the box-sizing in plugins or other components that leverage other behavior.” That was only a good interim strategy while browsers like Internet Explorer 5-6 did not support border-box, and browsers like Firefox 3-22 required a moz prefix.