body {
    background-image: url('img/stars.gif');
    font-family: 'Gulim', sans-serif;
    color: black;
    text-align: center;
    margin: 0;
    padding: 0;
}

.header {
    background-color: magenta;
    color: white;
    font-size: 28px;
    padding: 20px;
}

.popup {
    background-color: white;
    width: 60%;
    margin: 30px auto;
    padding: 20px;
    border: 5px solid blue;
    box-shadow: 5px 5px 15px rgba(0,0,0,0.5);
}