Replace phyiscal properties (top/bottom/left/right) with logical
properties (start/end) that can be used in non-LTR contexts (e.g.,
content in Arabic or Hebrew).
Based on the CSS Logical Properties and Values Level 1 specification,
currently an Editor's Draft [1].
Referencing MDN, all major browsers except Internet Explorer support the
margin, padding, and border properties.
[1]: https://drafts.csswg.org/css-logical/
Signed-off-by: Tim Crawford <crawfxrd@gmail.com>
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