TwentyTwentyOne Theme style.css has errors

Hi, just upgraded to WP 5.6 with TwentyTwentyOne theme. The application itself seems to work fine. But when I open it with my PhpStorm IDE, the style.css file shows many errors. Most are related to many -- variables are not defined. But below caught my attention the most:

@media only screen and (min-width: 482px) {

	.primary-navigation > div > .menu-wrapper li {
		margin: 0;
		width: inherit;
	}

	.primary-navigation > div > .menu-wrapper li:last-child() {
		margin-right: 0;
	}
}

The IDE highlight last-child() as error. Why do we need a parentheses here?

• This topic was modified 3 years, 11 months ago by activecoder.