bootstrap set navtabs border

.nav-tabs > li.active > a, .nav-tabs > li.active > a:hover, .nav-tabs > li.active > a:focus {
{
    border-color: #DDDDDD #DDDDDD transparent;
}

ref:
http://stackoverflow.com/questions/18949634/bootstrap-3-strange-thin-line-under-navtabs-in-firefox