JSBIN DEMO
Could this be a mistake or is it a bug?
Shouldn't the dark gray shade be darker than the default grey one?
HTML
<div class="lightgrey">Light Grey</div>
<div class="grey">Grey</div>
<div class="darkgrey">Dark Grey</div>
CSS
.lightgrey {background: lightgrey}
.grey {background: grey}
.darkgrey {background: darkgrey}