body {
    background: url('../img/bg.jpg');
    background-repeat: no-repeat;
    background-position: center center;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

.signup {
    text-align: center;
    background-color: white;
    padding: 10px;
    margin-top: 50px;
    border-radius: 20px;
}