<a href="#" class="border-button"> Hover me </a>
<a href="#" class="border-button"> Hover me, also </a>

.border-button {
  box-shadow: 0px 0px 0px 5px @border;
  transition: box-shadow 0.6s linear;
  margin: 0.5em;
}

.border-button:hover { box-shadow: 0px 0px 0px 10px @border; }