Invalid CSS class called in style.css

Heya, this is taken from the twenty fourteen style.css, lines 955-961:

.site-navigation .current_page_item > a,
.site-navigation .current_page_ancestor > a,
.site-navigation .current-menu-item > a,
.site-navigation .current-menu-ancestor > a {
	color: #55d737;
	font-weight: 900;
}

You’re styling an a element within a parent element with the class “current_page_ancestor”, when in fact WordPress outputs a parent element with the class “current-page-ancestor”. Line 956 should say:

.site-navigation .current-page-ancestor > a,

Mind the dashes. Or styling will fail.
Hope I helped! 🙂