后伪元素的大小问题

Issue with size of after pseudo element

link 元素上的伪元素 :after 有点问题。

div {
  width: 250px;
  border: 1px solid red;
}
/* line 1, sass/partials/_sidebar.sass */

.pagenav {
  list-style-type: none;
}
/* line 3, sass/partials/_sidebar.sass */

.pagenav ul {
  list-style-type: none;
  margin-left: 0;
  margin-top: 30px;
}
/* line 7, sass/partials/_sidebar.sass */

.pagenav ul li {
  padding-bottom: 10px;
}
/* line 9, sass/partials/_sidebar.sass */

.pagenav ul li a {
  text-decoration: none;
  padding-bottom: 8px;
  position: relative;
  -webkit-transition: all .3s ease-in-out;
  -moz-transition: all .3s ease-in-out;
  transition: all .3s ease-in-out;
  color: #404040;
  font-size: 18px;
}
/* line 16, sass/partials/_sidebar.sass */

.pagenav ul li a:hover,
.pagenav ul li a:focus,
.pagenav ul li a.active {
  color: darkgreen;
}
/* line 18, sass/partials/_sidebar.sass */

.pagenav ul li a:hover:after,
.pagenav ul li a:focus:after,
.pagenav ul li a.active:after {
  height: 3px;
  opacity: 1;
  -webkit-transform: translateY(0px);
  -moz-transform: translateY(0px);
  -ms-transform: translateY(0px);
  -o-transform: translateY(0px);
  transform: translateY(0px);
}
/* line 22, sass/partials/_sidebar.sass */

.pagenav ul li a:after {
  display: inline-block;
  -webkit-transition: all .3s;
  -moz-transition: all .3s;
  transition: all .3s;
  position: absolute;
  top: 100%;
  left: 12.5%;
  width: 75%;
  height: 1px;
  background: darkgreen;
  content: "";
  opacity: 0;
  -webkit-transform: translateY(-8px);
  -moz-transform: translateY(-8px);
  -ms-transform: translateY(-8px);
  -o-transform: translateY(-8px);
  transform: translateY(-8px);
}
<div>
  <li class="pagenav">
    <ul>
      <li>
        <a href="#">No problem here</a>
      </li>
      <li>
        <a href="#">A text longer than the first is a problem</a>
      </li>
      <li>
        <a href="#">No problem</a>
      </li>
    </ul>
  </li>
</div>

可以看到,如果一个link比div长,有一个换行但是伪元素集是从文本开始到结束的大小。

我不知道为什么,我已经测试过将 display : block 放入我的 link 但这不是我想要的,因为 :after 的大小不会"responsive" 到 link.

的大小

您应该可以通过将 link 设为 inline-block 元素来解决您的问题:

div {
  width: 250px;
  border: 1px solid red;
}
/* line 1, sass/partials/_sidebar.sass */

.pagenav {
  list-style-type: none;
}
/* line 3, sass/partials/_sidebar.sass */

.pagenav ul {
  list-style-type: none;
  margin-left: 0;
  margin-top: 30px;
}
/* line 7, sass/partials/_sidebar.sass */

.pagenav ul li {
  padding-bottom: 10px;
}
/* line 9, sass/partials/_sidebar.sass */

.pagenav ul li a {
  display:inline-block;
  text-decoration: none;
  padding-bottom: 8px;
  position: relative;
  -webkit-transition: all .3s ease-in-out;
  -moz-transition: all .3s ease-in-out;
  transition: all .3s ease-in-out;
  color: #404040;
  font-size: 18px;
}
/* line 16, sass/partials/_sidebar.sass */

.pagenav ul li a:hover,
.pagenav ul li a:focus,
.pagenav ul li a.active {
  color: darkgreen;
}
/* line 18, sass/partials/_sidebar.sass */

.pagenav ul li a:hover:after,
.pagenav ul li a:focus:after,
.pagenav ul li a.active:after {
  height: 3px;
  opacity: 1;
  -webkit-transform: translateY(0px);
  -moz-transform: translateY(0px);
  -ms-transform: translateY(0px);
  -o-transform: translateY(0px);
  transform: translateY(0px);
}
/* line 22, sass/partials/_sidebar.sass */

.pagenav ul li a:after {
  display: block;
  -webkit-transition: all .3s;
  -moz-transition: all .3s;
  transition: all .3s;
  position: absolute;
  top: 100%;
  left: 12.5%;
  right: 12.5%;
  height: 1px;
  background: darkgreen;
  content: "";
  opacity: 0;
  -webkit-transform: translateY(-8px);
  -moz-transform: translateY(-8px);
  -ms-transform: translateY(-8px);
  -o-transform: translateY(-8px);
  transform: translateY(-8px);
}
<div>
  <li class="pagenav">
    <ul>
      <li>
        <a href="#">No problem here</a>
      </li>
      <li>
        <a href="#">A text longer than the first is a problem</a>
      </li>
      <li>
        <a href="#">No problem</a>
      </li>
    </ul>
  </li>
</div>