html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
}

.bg-login {
    min-height: 100vh;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;

    background-image: url('../images/bg-login.png');
    background-size: contain;
    /* 🔥 no cropping */
    background-position: center;
    background-repeat: no-repeat;
    background-color: #000;
    /* optional */
}

/* form box */
.form-signin {
    width: 100%;
    max-width: 400px;
    padding: 20px;
    background: rgba(0, 0, 0, 0.30);
    border-radius: 10px;
}

.btn-fullscreen {
    cursor: pointer;
    color: #fff;
}