Quantity Queries http://alistapart.com/article/quantity-queries-for-css
li:nth-last-child(6):first-child,
li:nth-last-child(6):first-child ~ li {
/* applies only if there are exactly 6 list items */
}
li:nth-last-child(n+6),
li:nth-last-child(n+6) ~ li {
/* applies only if there are MORE than 6 list items */
}