https://drafts.csswg.org/css-logical-1/defines properties and values to control layout through logical, rather than physical, direction and dimension mappings. I have been working on implementing this in Blink, now I'm starting with WebKit. Various properties are already supported but using non-standard names with a -webkit- prefix. The standard properties have already been shipped in Firefox and Blink, so I will start with implementing them and converting the prefixed ones into aliases. This will happen in https://bugs.webkit.org/show_bug.cgi?id=188386, the specific list of properties is: * margin-{block,inline}-{start,end} * padding-{block,inline}-{start,end} * border-{block,inline}-{start,end} * border-{block,inline}-{start,end}-{width,style,color} * {block,inline}-size * {min,max}-{block,inline}-size See Blink's Intent to Ship: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/tkN-r119eNc <https://groups.google.com/a/chromium.org/forum/#%21topic/blink-dev/tkN-r119eNc> After this I willcontinue withthe remaining flow-relative box model properties and the flow-relative values for existing properties: * margin-{block,inline} * padding-{block,inline} * border-{block,inline} * border-{block,inline}-{width,style,color} * float: inline-{start,end} * clear: inline-{start,end} * resize: {block,inline} This will be behind an experimentalflag, like it's being done in Blink. Firefox shipped some. See Blink's Intent to Implement: https://groups.google.com/a/chromium.org/d/msg/blink-dev/48OwfwZrbvI/A1XZFGk... I would like to get your feedback and comments about this topic, if you are fine with the plan we will start to land patches next week.