body {
    background-image: url("./bmi-bg.jpg");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    margin: 0;
    font-family: Arial, sans-serif;
}

form {
    max-width: 90%;
}

@media (min-width: 768px) {
    form {
        max-width: 50%;
    }
}

@media (min-width: 992px) {
    form {
        max-width: 30%;
    }
}