nav a {
    color: #ffffff;
    position: relative;
    text-decoration: none;
}

nav a::before {
  margin-block: -2px;
  content: '';
  position: absolute;
  width: 100%;
  height: 2px;
  background-color: hsl(321, 93%, 48%);
  bottom: 0;
  left: 0;
  transform-origin: right;
  transform: scaleX(0);
  transition: transform .4s ease-in-out;
  border-radius: 5px;
}

nav a:hover::before {
  transform-origin: left;
  transform: scaleX(1);
}