JSFiddle - React, Tailwind, and code Playground

HTML

<div class="full-width-wrap">

  <div class="shaped">
    Some text
  </div>

</div>

CSS

.full-width-wrap {
  width: 100%;
  border-bottom: 1px solid red;
}

.shaped {
  line-height: 1.5em;
  border-bottom: 1.5em solid red;
  border-right: 50px solid transparent;
  height: 0;
  width: 300px;
}