Its working for me. I went to Look and Feel -> Custom CSS, checked the box "Use custom css" and added the following:
Code:
@media (min-width: 480px) {
#sidebar-first {
padding-right: 60px;
padding-left: 60px;
}
}
It did what I expected, added 60px on both sides of the first menu section. Does this not work for you?