.btn {
  display: grid;
  grid-auto-flow: column;
  align-items: center;
  justify-content: center;
  max-width: 400px;
  margin-inline: auto;
  padding: 10px;
  border-radius: 10px;
  background: #EFEFEF;
  text-decoration: none;
  color: inherit;
}

.btn::after {
  position: relative;
  top: -1px;
  content: "";
  margin-left: 5px;
  width: 7px;
  height: 7px;
  border-right: 2px solid #000;
  border-bottom: 2px solid #000;
  transform: rotate(-45deg);
}