body {
    background-image: url('../img/gambar.jpg');
    background-position: center;
    background-size: cover;
    min-height: 100vh;
    display: flex;
    align-items: center;
}
.login-card {
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
    border-radius: 15px;
}