#popup {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
}

#popup-content {
    position: relative;
    background-color: #fefefe;
    padding: 20px;
    border-radius: 10px;
    width: 40%;
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
    text-align: center;
}

#popup-close {
    position: absolute;
    top: 20px;
    right: 20px;
    color: #aaa;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

#popup-close:hover {
    color: black;
}

@media screen and (max-width: 600px) {
    #popup-content {
        width: 90%;
    }
}