css - z-index 不适用于::after/::before 元素？

Question

z-index 不适用于其 ::before/::after 元素。我在下面分享代码。

.or {
  border: 2px solid #8fc300;
  border-radius: 5px;
  color: #333;
  font-size: 17px;
  font-weight: 600;
  height: 34px;
  line-height: 26px;
  text-align: center;
  width: 34px;
  margin-top: 64px;
  margin-left: 20px;
  margin-right: 20px;
  background: #fff;
  /*For z-index - keep the green area on top*/
  position: relative;
  z-index: 11;
}
.or::after {
  background: red;
  content: "";
  display: block;
  height: 116px;
  margin-left: 15px;
  margin-top: -68px;
  width: 4px;
  /*For z-index - keep the green area on top*/
  position: relative;
  z-index: 9;
}

<div class="or"></div>

Answer 1

您可以从父元素中删除 z-index 并在伪元素上使用负值 z-index: -1。如果你只想要红线上的绿线，你还需要从父级中删除白色背景 DEMO

.or {
  border: 2px solid #8fc300;
  border-radius: 5px;
  color: #333;
  font-size: 17px;
  font-weight: 600;
  height: 34px;
  line-height: 26px;
  text-align: center;
  width: 34px;
  margin-top: 64px;
  margin-left: 20px;
  margin-right: 20px;
  background: #fff;
  /*For z-index - keep the green area on top*/
  position: relative;
}
.or::after {
  background: red;
  content: "";
  display: block;
  height: 116px;
  margin-left: 15px;
  margin-top: -68px;
  width: 4px;
  /*For z-index - keep the green area on top*/
  position: absolute;
  z-index: -1;
}

<div class="or"></div>