<div><a href="#">Tab 1</a></div>
<div class="active"><a href="#">Tab 2</a></div>
<div><a href="#">Tab 3</a></div>
<div><a href="#">Tab 4</a></div>
<div><a href="#">Tab 5</a></div>
div {
  height: 0px;
  width: 100px;
  float: left;
  background: transparent;
  border-right: 30px solid transparent;
  border-bottom: 80px solid #c5bbf7;
  text-align: center;
}

a {
  line-height: 80px;
}

.active {
  border-bottom: 80px solid #8671ed;
}
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