Edit in JSFiddle

button {
  background-color: lightsteelblue;
  border: none;
  border-radius: 0.2em;
  padding: 0.5em 1em;
  box-shadow: 0 0.2em steelblue;
  font: inherit;
  cursor: pointer;
}

button:hover, button:focus {
  opacity: 0.8;
  outline: none;
}

button:active {
  position: relative;
  top: 0.1em;
  box-shadow: 0 0.1em steelblue;
}
<button>Click me!</button>