* { border-box: box-sizing; }

.btn {
  padding: 0;
  font-size: 16px;
  height: max-content;
  align-items: center;
  appearance: none;
  border: 0;
  line-height: 2;
  
  &::before {
    display: block;
    content: "";
    width: 0;
    height: 0;
    margin-block: calc((1em - 1lh) / 2);
  }
  
  &::after {
    display: block;
    content: "";
    width: 0;
    height: 0;
    margin-block: calc((1em - 1lh) / 2);
  }
}

.container {
  width: 500px;
  margin: 5em auto;
  height: 25vh;
}

p {margin: 0;}