I have a li list with 2 items in it, which are "RMS" and "RPM". When you rollover RMS the background changes and the RPM is targeted with the following to make the RPM element change to red. I need the same thing to work for the opposite side as well (rollover RPM and the background changes but RMS isn't targeted). I can't seem to get it to work for some reason.
li:hover + li#RPM {
background-color:red;
}
li:hover + li#RMS {
background-color: #CCC;
}