button,
.btn {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    -webkit-border-radius: 0;
    -moz-border-radius: 0;
    border-radius: 0;
    padding: 0;
    margin: 0;
    border: 0;
    -webkit-box-shadow: none;
    -moz-box-shadow: none;
    box-shadow: none;
}