How to exclude Login button from header nav items hover effects

I am using this code for a nice underline effect on hover. It is for all header nav items but it is also applying to my login button. How to I exclude my login button so it is not effected by the code? 

.header-nav-item::after {
  content: '';
  background-color: #a9a285;
  height: 4px; //thickness
  width: 0;
  display: block;
  margin-top: 0px !important;
  transform: scaleX(1);
  transition: width .7s ease; 
  margin: 1 auto;
}

.header-nav-item:hover::after {
  width: 100%;
}

.header-nav-item--active a {
    background-image: none !important;
}