body {
    display: -ms-flexbox;
    display: -webkit-box;
    display: flex;
    -ms-flex-align: center;
    -ms-flex-pack: center;
    -webkit-box-align: center;
    align-items: center;
    -webkit-box-pack: center;
    justify-content: center;
    padding-top: 40px;
    padding-bottom: 40px;
    background-color: #f0f0f0;
}

form {
    max-width:450px;
    padding:10px;
}