RTL issue with submenu

There is a problem with line positions, should be on the left of every item instead the last
and now it is on the left of all instead the first…

In RTL it should be:

#top .av-subnav-menu > li:last-child a {
border-left: none;
}

instead of:

#top .av-subnav-menu > li:first-child a {
border-left: none;
}

what can I do about this? I could add add the first line of code but then I’m missing a line….