button {
  color: #090909;
  padding: 0.7em 1.7em;
  font-size: 18px;
  border-radius: 0.5em;
  background: #e8e8e8;
  cursor: pointer;
  border: 1px solid #e8e8e8;
  transition: all 0.3s;
  box-shadow:
    6px 6px 12px #c5c5c5,
    -6px -6px 12px #ffffff;
}

button:active {
  color: #666;
  box-shadow:
    0px 0px 0px #c5c5c5,
    0px 0px 0px #ffffff,
    inset 4px 4px 12px #c5c5c5,
    inset -4px -4px 12px #ffffff;
}