Menu Font Cannot be changed

First of all, this was never a problem before. But now, i cannot change the menu font color. I’ve tried the following CSS codes and it doesn’t work.

mainnav ul li a {

font-size: 16px;
color: #ff0099;
}
.main-header #mainnav ul li a {
color: #ff0099 !important;
}

The page I need help with: [log in to see the link]