When you give width to the line, the text-align: centre doesn't work how do I solve this?
.line-center {
  margin: 0;
  padding: 0 10px;
  background: #fff;
  display: inline-block;
}
h2 {
  text-align: center;
  position: relative;
  z-index: 2;
  width: 200px;
}
h2:after {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  border-top: solid 1px red;
  z-index: -1;
}<h2><span class="line-center">Test</span></h2> 
     
    