body {
    background-image: url('../img/back.jpg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
    margin: 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
        
}

label.required:after {
    content: " *";
    color: #dc3545;
}