JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
  <h1>Заголовок</h1>
</div>

CSS

.wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
}
h1 {
  border-bottom: 5px solid #000;
  position: relative;
}
h1:after {
  content: "";
  position: absolute;
  bottom: -15px;
  border-bottom: 5px solid #000;
  width: 100%;
  left: 0;
}