.popup-overlay {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    background-color: rgba(0,0,0,0.7); /* Black background with opacity */
    justify-content: center;
    align-items: center;
}

.popup-content {
    background-color: #fefefe;
    margin: auto; /* Center the box */
    padding: 20px;
    border: 1px solid #888;
    width: 80%; /* Could be more or less, depending on screen size */
    max-width: 500px;
    border-radius: 10px;
    text-align: center;
    position: relative;
}

.close-btn {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    position: absolute;
    top: 10px;
    right: 15px;
}

.close-btn:hover,
.close-btn:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}