<div class="btn-wrap">
  <button class="exitE" type="button" title="Exit" aria-label="Exit"></button>
</div>
body {
  background: #121212;
}
.btn-wrap {
  position: relative;
  z-index: 0;
  padding: 0 0;
  margin: 47px 0 0;
  border-top: 1px solid blue;
}
.exitE {
  position: relative;
  z-index: auto;
  margin: -25px auto 0;
  inset: 0 0 0 0;
  width: 47px;
  height: 47px;
  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
  background: black;
  border-radius: 50%;
  border: 5px solid #0059dd;
  display: flex;
  cursor: pointer;
}
.exitE:after {
  content: "";
  position: absolute;
  z-index: -1;
  background: #121212;
  left: -11px;
  top: -11px;
  width: 57px;
  height: 30px;
  border: 1px solid blue;
  border-bottom: transparent;
  border-radius: 30px 30px 0 0;
}
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