fix text low-contrast/drpdow/collapsed/link/active

to fix the text low-contrast, when collapsed a link active in dropdownmenu.

> in @media (max-width: 979px)

> after this:
.nav-collapse .dropdown-menu a {
    padding: 9px 15px;
    font-weight: bold;
    color: #777777;
    -webkit-border-radius: 3px;
       -moz-border-radius: 3px;
            border-radius: 3px;
  }

> put this:
   .nav-collapse .dropdown-menu .active a{
	color: #ffffff;
   }