PostCSS-RTLCSS-Combined 
PostCSS plugin that creates a combined LTR/RTL stylesheet
.foo {
color: red;
left: 10px;
border-color: red blue green orange
}
.foo {
color: red;
border-color: red blue green orange
}
html[dir="ltr"] .foo {
left: 10px
}
html[dir="rtl"] .foo {
border-color: red orange green blue;
right: 10px
}
Usage
postcss([ require('postcss-rtlcss-combined') ])
See PostCSS docs for examples for your environment.