.btn.btn-nav{

}
.btn.btn-nav:first-child{
  border-top-right-radius: 0px;
  border-bottom-right-radius: 0px;
  border-right: 1px solid #fff;
}

.btn.btn-nav:last-child{
  border-top-left-radius: 0px;
  border-bottom-left-radius: 0px;
  border-left: 0px solid #fff;
}

.btn.btn-nav:nth-child(2):not(:last-child){
  border-radius: 0px;
}
.btn.btn-nav.active{
  background-color: #000;
  border-color: #000;
  color: #FFF;
}