<a href="#" data-content="Link Hover">Link Hover</a>

@import url('https://fonts.googleapis.com/css?family=Barlow:800&display=swap');

* {
  box-sizing: border-box;
  &::before, &::after {
    box-sizing: border-box;
  }
}

body {
  font-family: 'Barlow', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  min-height: 100vh;
}

a {
  position: relative;
  display: inline-block;
  font-size: 2em;
  color: royalblue;
  font-weight: 800;
  text-decoration: underline;
  // text-decoration: none;
  overflow: hidden;
  &::before {
    position: absolute;
    content: attr(data-content);
    top: 0;
    left: 0;
    width: 0;
    // height: 0;
    color: midnightblue;
    text-decoration: underline;
    white-space: nowrap;
    overflow: hidden;
    transition: width 275ms ease;
    // transition: height 275ms ease;
  }
  &:hover::before {
    width: 100%;
    // height: 100%;
  }
}