form.contact-formn.my_form {
    padding: 20px;
    max-width: 400px;
    display: block;
    margin: 0 auto;
}
button.btn-primary.btn-submit {
    display: block;
    margin: 0 auto;
    float: none;
}
button.btn-primary.btn-submit.my_btn {
    background: #c99035;
    color: white;
    text-shadow: -1px 1px 1px black;
}