JSFiddle - React, Tailwind, and code Playground

by shigetak

HTML

<a href="#">オトクな定期便を申し込む</a>

CSS

a {
  position: relative;
  display: inline-block;
  padding: .4em;
  text-decoration: none;
}
a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 25px;
  -webkit-transform: scaleX(0);
  -ms-transform: scaleX(0);
  transform: scaleX(0);
  background-color: red;
  -webkit-transition: all .3s ease;
  transition: all .3s ease;
  
}
a:hover::after {
  -webkit-transform: scaleX(1);
  -ms-transform: scaleX(1);
  transform: scaleX(1);
}