discourse/app/assets/stylesheets/common/base/rtl.scss

// Right to left styles.
// *** These styles are all going to be flipped by the r2 gem ***
// There may be a 'do not flip' flag that can be used, but I haven't found it.

// Keep the topic admin menu on the page
.rtl .topic-admin-menu {
  right: 0 !important;
}

// This is used to flip the .fa-caret-right icon
@mixin rotate( $degrees ) {
  -webkit-transform: rotate(#{$degrees}deg);
  -moz-transform: rotate(#{$degrees}deg);
  -ms-transform: rotate(#{$degrees}deg);
  -o-transform: rotate(#{$degrees}deg);
  transform: rotate(#{$degrees}deg);

  filter:  progid:DXImageTransform.Microsoft.Matrix(sizingMethod='auto expand', M11=#{cos($degrees)}, M12=-#{sin($degrees)}, M21=#{sin($degrees)}, M22=#{cos($degrees)});
  -ms-filter: "progid:DXImageTransform.Microsoft.Matrix(sizingMethod='auto expand', M11=#{cos($degrees)}, M12=-#{sin($degrees)}, M21=#{sin($degrees)}, M22=#{cos($degrees)})";
  zoom: 1;
}

// Get the right caret to point left
.rtl .fa-caret-right {
  @include rotate(180);
}

// Changes the triangle arrow direction in .nav-stacked .active
// The 'left' and 'right' in these selectors is not being flipped by r2.
.rtl .nav-stacked .active > a::after {
  border-left-color: transparent !important;
  border-right-color: $secondary !important;
}