A CodePen by Manoz.

index.html

<button>Normal button</button>

style.css

body {
    background: #ede9e9;
}

button {
    padding: 10px 30px;
    border: 1px solid #d8d8d8;
    border-radius: 3px;
    text-transform: uppercase;
    font-family: Helvetica,Arial,sans-serif;
    font-size: 16px;
    color: #777777;
    background: #fff;
    -webkit-box-shadow: 0 1px 0 #d8d8d8;
    box-shadow: 0 1px 0 #d8d8d8;
}

button:hover {
    border: 1px solid #b9b9b9;
    -webkit-box-shadow: 0 1px 0 #b9b9b9;
    box-shadow: 0 1px 0 #b9b9b9;
}

button:active {
  border: 1px solid #d9d9d9;
  background: #f2eeee;
  box-shadow: inset 0 0 6px  rgba(0,0,0,.15);
}