body {
    background-image: url(../img/bg.jpeg);
    background-size: cover;
}

.card {
    border: black solid;
    margin-top: 100px;
    margin-left: 310px;
    padding: 30px;
    width: 500px;
}

.form-group {
    width: 50%;
    margin-left: 120px;
}

.btn {
    margin-left: 160px;
    width: 30%;
}

@media (max-width: 768px) {
    .card {
        border: black solid;
        margin-top: 100px;
        margin-left: 20px;
        padding: 30px;
        width: 300px;
    }
    
    .form-group {
        width: 100%;
        margin-left: 10px;
    }
    
    .btn {
        margin-left: 60px;
        width: 30%;
    }
}