Vantage Premium – Custom CSS for Menu

I have an issue with Vantage Premium after updating to the latest version. I had custom CSS that would display a down arrow character in the menu if a sub-menu was present. This no longer works. The custom CSS was as follows:

.menu li.has-children > a:after {
color: #fff;
content: ‘ ▼’;
font-size: 13px;
vertical-align: 1px;
}
.menu li li.has-children > a:after {
color: #222;
content: ‘ ►’;
font-size: 10px;
vertical-align: 1px;
}

Can someone please help? Thank you!