.popup {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: rgba(255, 255, 255, 0.9);
    padding: 20px;
    border: 2px solid #333;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.5);
    z-index: 9999;
    animation: popupAnimation 0.5s ease-in-out;
}

@keyframes popupAnimation {
    0% {
        transform: scale(0);
    }
    100% {
        transform: scale(1);
    }
}

.flashing-text {
    font-size: 24px;
    color: red;
    animation: flash 1s infinite;
}

@keyframes flash {
    0% {
        opacity: 1;
    }
    50% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}