<button>
    <span>Button</span><i></i>
</button>
<style>
/* From Uiverse.io by mrhyddenn - Tags: button */
button {
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 10px 30px;
  transition: 0.5s;
  position: relative;
  font-size: 17px;
  background: #333;
  border: none;
  color: #fff;
}

button:hover {
  letter-spacing: 0.25em;
  background: #ff1867;
  color: #ff1867;
  box-shadow: 0 0 45px #ff1867;
}

button::before {
  content: '';
  position: absolute;
  inset: 2px;
  background: #2222