Bug: Validator doesn't recognize purely numeric argument for :nth-child()

[tmb-github]

/*
It doesn't recognize a purely numeric argument for :nth-child(), instead expecting the format 2a+b.
See: https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child
*/

.header-ul li:nth-child(2) {
padding-top: 1.5rem;
}

[ylafon]

Hum, definitely a new bug introduced by proper (well, not really) parsing of An+B