跨越多行的CSS伪元素

Question

我在链接下有一条动画线。它适用于单行链接，但有些链接用换行符<br>隔开有没有办法使动画下划线沿着链接的所有行显示出来？谢谢

body {
  padding: 20px;
  font-family: Helvetica;
}

  a{
    font-weight: bold;
    color: black;
    position: relative;
    text-decoration: none;
  }
  a::before {
    content: "";
    position: absolute;
    width: 0%;
    height: 2px;
    bottom: 0;
    background-color: #000;
    transition: all 0.2s;
  }
  a:hover::before {
    width: 100%;
  }

<a href="">my link</a>
<br><br>
<a href="">this is<br>a much<br>longer link</a>

Answer 1

body {
  padding: 20px;
  font-family: Helvetica;
}

a {
  font-weight: bold;
  color: black;
  position: relative;
  text-decoration: none;
  background:linear-gradient(#000,#000) left bottom no-repeat;
  background-size:0% 2px;
  transition: all 0.5s;
}

a:hover {
  background-size:100% 2px;
}
/* this will give another kind of animation (all lines will animate at the same time)*/
.alt {
  -webkit-box-decoration-break:clone;
          box-decoration-break:clone;
}

<a href="">my link</a>
<br><br>
<a href="">this is<br>a much<br>longer link</a>
<br><br>
<a class="alt" href="">this is<br>a much<br>longer link</a>

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