<p>hogehoge <a href="#">fugafuga</a> piyopiyo.</p>
/*Source: https://theoutline.com/post/5970/unconventional-wisdom-emotional-readiness-is-bullshit*/
:root {
  --mainColor: #ff9800;
}

body {
  align-items: center;
  display: flex;
  font-size: 2em;
  height: 100vh;
  justify-content: center;
}

a {
  background: linear-gradient(to bottom, var(--mainColor) 0%, var(--mainColor) 100%);
	background-position: 0 100%;
	background-repeat: repeat-x;
	background-size: 3px 3px;
  color: #000;
  text-decoration: none;
}

a:hover {
  background-image: url("data:image/svg+xml;charset=utf8,%3Csvg id='squiggle-link' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' xmlns:ev='http://www.w3.org/2001/xml-events' viewBox='0 0 20 4'%3E%3Cstyle type='text/css'%3E.squiggle{animation:shift .3s linear infinite;}@keyframes shift {from {transform:translateX(0);}to {transform:translateX(-20px);}}%3C/style%3E%3Cpath fill='none' stroke='%23ff9800' stroke-width='2' class='squiggle' d='M0,3.5 c 5,0,5,-3,10,-3 s 5,3,10,3 c 5,0,5,-3,10,-3 s 5,3,10,3'/%3E%3C/svg%3E");
  background-position: 0 100%;
  background-size: auto 6px;
  background-repeat: repeat-x;
  text-decoration: none;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.