You could rotate the parent element 180deg and then rotate the children elements -180deg.
ul {
transform: rotate(180deg);
}
ul > li {
transform: rotate(-180deg);
}
Example Here
Alternatively, you could use flex boxes along with the order property.
Although this isn’t technically reversing the order, you could also use counter-increment along with a psuedo element.
Example Here
ul {
list-style-type:none;
counter-reset:item 6;
}
ul > li {
counter-increment:item -1;
}
ul > li:after {
content: counter(item);
}